Factions–In Divergent, you choose a faction to become your tribe. Who do you choose?

Image: Flame in octagonal bowl. Text: Choose your FACTION! -- In Divergent, you choose a faction to become your tribe. Who do you choose!
Photo by KS Kyung (unsplash.com/@mygallery)

Choose your destiny! Choose your tribe!

In the wizarding world of Harry Potter, the students of Hogwarts are sorted into four houses. And, of course, the famous Sorting Hat chooses your house for you.

Young Adult books are about finding yourself. (And Middle Grade books, too!) And part of finding yourself is finding your “tribe,” the type of people you want to hang out with. The kind of people you want to become.

Let’s explore the tribes in a Sci Fi standout: Divergent.

In Divergent, by Veronica Roth, at age sixteen you must choose from one of five factions. You can choose to remain in the faction that raised you. Or you can risk joining another faction. If you fail the tests, you become one of the homeless outcasts, the factionless, a fate worse than death!

Cover of Divergent by Veronica Roth. Image: Flaming bowl of fire imposed over Chicago's skyline

Welcome to the Choosing Ceremony

“Welcome to the Choosing Ceremony. Welcome to the day we honor the democratic philosophy of our ancestors, which tells us that every man has the right to choose his own way in this world.

. . . .

“Our dependents are now sixteen. They stand on the precipice of adulthood, and it is now up to them to decide what kind of people they will be . . . . Decades ago our ancestors realized that it was not political ideology, religious belief, race, or nationalism that is to blame for a warring world. Rather, they determined that it was the fault of human personality–of humankind’s inclination toward evil, in whatever form that is. They divided into factions that sought to eradicate those qualities they believed responsible for the world’s disarray.”

[I]t is now up to them to decide what kind of people they will be.

“Those who blamed aggression formed Amity.”


“The Amity exchange smiles. They are dressed comfortably, in red or yellow. Every time I see them, they seem kind, loving, free. But joining them has never been an option for me.”

“Those who blamed ignorance became the Erudite.”


“And when they clear out [my brother Caleb’s] room, what will they discover? I imagine books jammed between the dresser and the wall, books under his mattress. The Erudite thirst for knowledge filling all the hidden places in his room.”

. . . .

“A long time ago, Erudite pursued knowledge and ingenuity for the sake of doing good. Now they pursue knowledge and ingenuity with greed in their hearts.”

“Those who blamed duplicity created Candor.”


“The Candor man wears a black suit with a white tie–Candor standard uniform. Their faction values honesty and sees the truth as black and white, so that is what they wear.”

“Those who blamed selfishness made Abnegation.”


Gray hoodie worn by someone waiting for a train

“The houses on my street are all the same size and shape. They are made of gray cement, with few windows, in economical, no-nonsense rectangles. Their lawns are crabgrass and their mailboxes are dull metal. To some the sight might be gloomy, but to me their simplicity is comforting.

If we have little, and want for little, and we are all equal, we envy no one.

“The reason for the simplicity isn’t disdain for uniqueness, as the other factions have sometimes interpreted it. Everything–our houses, our clothes, our hairstyles–is meant to help us forget ourselves and to protect us from vanity, greed, and envy, which are just forms of selfishness. If we have little, and want for little, and we are all equal, we envy no one.

“I try to love it.”

. . . .

“I blame selfishness; I do.”

. . . .

“But I am not selfless enough. Sixteen years of trying and I am not enough.”

“And those who blamed cowardice were the Dauntless.”


Back of shaved head; white gauge in ear; dagger tattoo behind ear
Photo by Panos Sakalakis (unsplash.com/@meymigrou)

“In front of [the school] is a large metal sculpture that the Dauntless climb after school, daring each other to go higher and higher. Last year I watched one of them fall and break her leg.”

. . . .

“At exactly 7:25, the Dauntless prove their bravery by jumping from a moving train.

“My father calls the Dauntless ‘hellions.’ They are pierced, tattooed, and black clothed. Their primary purpose is to guard the fence that surrounds our city. From what, I don’t know.”

Choose your faction!

“In the last circle are five metal bowls so large they could hold my entire body, if I curled up. Each one contains a substance that represents each faction: gray stones for Abnegation, water for Erudite, earth for Amity, lit coals for Dauntless, and glass for Candor.

I will cut into my hand and sprinkle my blood into the bowl of the faction I choose.

“When Marcus calls my name, I will walk to the center of the three circles. I will not speak. He will offer me a knife. I will cut into my hand and sprinkle my blood into the bowl of the faction I choose.”

Which faction will you choose?

Choose one of the five factions. Choose your tribe. How will you decide?

Please post your comments below.

Be stellar!

Matthew Cross

A review of Ready Player One by Ernest Cline–a sprawling Sci Fi adventure that explores nerd culture from the 1980s to the future

Cover of Ready Player One showing Wade Watts climbing the stacks.

Here’s an introduction to the sprawling science fiction blockbuster Ready Player One

The hero, Wade Watts, is a poor, orphaned teenager, whose real life exists on the OASIS, a massively multiplayer online game. He is stuck with a third-level avatar.  “Having a third-level avatar was a colossal embarrassment.”  Wade is a gunter, looking for the creator’s secret Easter Egg hidden in the OASIS.  “The Hunt, as the contest came to be known, quickly wove its way into global culture.  Like winning the lottery, finding Halliday’s Easter egg became a popular fantasy among adults and children alike. . . .  A new subculture was born, composed of the millions of people who now devoted every free moment of their lives to searching for Halliday’s egg.  At first, these individuals were known simply as ‘egg hunters,’ but this was quickly truncated to the nickname ‘gunters.’”

Cover of Ready Player One showing Wade climbing the stacks.

The story begins in the laundry room of Wade’s aunt’s trailer, which is in the Portland Avenue Stacks of Oklahoma City.  The stacks are neighborhoods of trailers-stacked-on-trailers in high-rise fashion.  Wade soon scampers to his hideout, the space in the back of a cargo van buried underneath a mound of discarded cars and trucks, where he can log into the OASIS.

The story moves to the OASIS, where most of the story occurs.  Here’s how Wade describes the OASIS:  “a massively multiplayer online game that had gradually evolved into the globally networked virtual reality most of humanity now used on a daily basis.”

The hero’s best friend is Aech, whose real identity and name were a secret.  “Aech pronounced his own avatar’s name just like the letter ‘H’” and he confided to Wade that his real first name began with the letter “H.”

Cover of Ready Player One showing cast members from the movie.

“Aech’s avatar was a tall, broad-shouldered Caucasian male with dark hair and brown eyes.  I’d asked him once if he looked anything like his avatar in real life, and he’d jokingly replied, ‘Yes.  But in real life, I’m even more handsome.’”

Aech is a senior at OPS #1172, a high school on the virtual education planet Ludus in the OASIS.  “He made quite a bit of dough competing in televised PvP arena games after school and on the weekends.  Aech was one of the highest-ranked combatants in the OASIS, in both the Deathmatch and Capture the Flag leagues.  He was even more famous than Art3mis.”  Aech is also a gunter.

In time, Wade and Aech meet the legendary Art3mis, pronounced “Artemis,” another gunter who is famous for her gunter blog, Arty’s Missives.  “Her avatar had a pretty face, but it wasn’t unnaturally perfect.  In the OASIS, you got used to seeing freakishly beautiful faces on everyone.  But Art3mis’s features didn’t look as though they’d been selected from a beauty drop-down menu on some avatar creation template.  Her face had the distinctive look of a real person’s, as if her true features had been scanned in and mapped onto her avatar.  Big hazel eyes, rounded cheekbones, a pointy chin, and a perpetual smirk.”

The villain is Innovative Online Industries (IOI).  IOI “was a global communications conglomerate and the world’s largest Internet service provider.  A large portion of IOI’s business centered around providing access to the OASIS and on selling goods and services inside it.  For this reason, IOI had attempted several hostile takeovers of Gregarious Simulation Systems [which controlled the OASIS], all of which had failed.”  

Stylized cover of Ready Player One showing a cross section of a head where the exposed brain looks like a maze puzzle

IOI also recruited legions of gunters to look for Halliday’s Easter egg.  These mercenaries of the OASIS are called “Sixers” because they all have six-digit employee numbers starting with the numeral “6.”  “To become a Sixer, you had to sign a contract stipulating, among other things, that if you found Halliday’s egg, the prize would become the sole property of your employer. . . .  The company also provided your avatar with high-end armor, vehicles, and weapons, and covered all of your teleportation fares.  Joining the Sixers was a lot like joining the military.”

This story feels like all your best memories of playing video games.  Any kind of game.  If you like space games, first-person shooters, quest games, arcade games, classic Atari, it does not matter.  Ernest Cline included them all in Ready Player One.  There is at least one scene dedicated to every kind of game, even video games that do not exist yet.  (The one exception may be sports games, unless you consider the jousting in Joust to be a sport.)

You should read this book because if you love reading fiction, then you probably love a good escape from reality.  Wade, the ultimate escapist who even goes to school in a virtual world, takes us on an epic journey through every kind of virtual adventure imaginable.

You may also want to read this book if you love 1980s movies, music, games and trivia.  Or if you love geek or nerd culture.  This book is chock full of references to everything we geeks and nerds love.  Everything!

Cover of Ready Player One showing the stacks in green schematic over black

If you read this book, you’d better not mind nerd culture, endless 1980s references, and the word “sucks.”  Wade likes that word a lot and a few other strong words now and then.  And you’d better not mind a long book.  It’s great, but it’s long.

Here’s a good part:  “I walked across the chamber to the foot of the dais.  From here I could see the lich more clearly.  His teeth were two rows of pointed cut diamonds arrayed in a lipless grin, and a large ruby was set in each of his eye sockets.

“For the first time since entering the tomb, I wasn’t sure what to do next.

Cover of Ready Player One showing gate, figure and key in 8-bit

“My chances of surviving one-on-one combat with a demi-lich were nonexistent.  My wimpy +1 Flaming Sword couldn’t even affect him, and the two magic rubies in his eye sockets had the power to suck out my avatar’s life force and kill me instantly.  Even a party of six or seven high-level avatars would have had a difficult time defeating him.”

Have you already read it?  What did you think?

If not, do you have a question about this book?  Give me a try.

Please post your comments below.

Be stellar!

Matthew Cross

What makes a GOOD ALIEN in science fiction?–Must they share human traits to be likable? How alien is too alien?

Headline image of feminine, punk-style alien with mohawk wearing headphones

If you love Sci Fi, you probably love a good alien encounter. But do you love the aliens or love-to-hate the aliens?

Humans have difficulty connecting with aliens that are too, well, alien. The more human they seem, the better are able to connect with them. This should not be too surprising given that we humans are social animals that (generally) thrive with social interaction with other humans.

Photo of smiling man's head and shoulders
A “mugshot.” Photo by Joseph Gonzalez (unsplash.com/@miracletwentyone).

I even learned in journalism school that people enjoy seeing photographs of people more than anything else. We were taught to include photos of people to liven up dull newspaper pages.  And if all you have is a “mug shot”–a photograph of a person’s face and (sometimes) shoulders–then use it! Readers are more likely to read a story that includes a photograph of a person’s face than a story with just a headline and text.

Photo by Garrett Jackson (unsplash.com/@jxnsartstudio).
Photo by Charles Deluvio (unsplash.com/@charlesdeluvio).

Babies? What’s so great about babies?

I have also read that humans are attracted to animals that superficially look like babies.  (After all everyone loves babies, even though they are mostly useless!) That is supposed to explain the popularity of certain breeds of dogs and cats with large eyes and round faces.  I don’t know if that’s true, but I do know that toy makers seem to make stuffed toy cats and dogs with bigger and rounder eyes every year.  (That drives Mrs. C crazy. She finds “big-eyed” dolls to be creepy.)  

Babies: Cute, adorable, mostly useless. Photo by Chayene Rafaela (unsplash.com/@chayene).

My Theory

So I’m proposing the theory that readers prefer creatures that approximate human appearance, habits and speech.  Also, I think we will accept close cousins, that is, creatures that remind us of the class of mammals. So things that appear warm-blooded and covered in skin or fur; things that look like cute dogs or cats or Teddy bears.  We also like these. It’s OK if they have six legs or six eyes. That’s the cool part that makes them alien; alien without being too alien.

Readers prefer creatures that approximate human appearance, habits and speech.

Photo by Francesco Ungaro (unsplash.com/@francesco_ungaro).

Reptile Men and Women

What about reptile men?  Well, if they have two arms and two legs, that’s a good start. If they have a face with two eyes and a mouth, then that’s pretty humanlike, even if they have forked tongues and scales instead of skin.  I still think they are more likely to be cast as baddies than good guys, especially in a movie. But in a book, if such a creature rescues a kitten (or a human child), I think we can all get on board with that. (Remember, kittens and babies are cute and people like them!) 

What about reptile women? Well, generally, the same goes for reptile women as reptile men. But, well, guys–meaning readers who are human males–seem to like almost all alien women. Why? Well . . . why do sailors like mermaids? That’s a subject for another blog.

What about dragons?

Cover of The Dragonriders of Pern by Anne McCaffrey

I think we all have a challenge liking creatures that are more reptile, amphibian, or even possibly avian than human, especially the intelligent ones.  Dragons may be the one exception. People do love dragons.

And, yes, there are plenty of dragons in Sci Fi. They are not only in fantasy. See Anne McCaffrey’s Dragonriders of Pern series.  Grand Master McCaffrey excels in disproving my point and making large, intelligent reptiles–reptiles that look nothing like humans–very lovable.  (Or is she the exception that proves the rule?)

Ruth, the white dragon, is a favorite of fans of the Pern series. Image from pern.fandom.com. Read more about Ruth the white dragon.

What is the problem with aliens that are not humanlike?

I think there are a couple of things at work here.  One is a natural fear of certain types of creatures found on Earth.  So, for example, if we are familiar with certain dangerous animals, such as snakes and spiders, then I propose writers will have a hard time making likeable aliens that remind us of those creatures.  And they make wonderful “bad guy” aliens.

Large boulder in Avebury, United Kingdom. Photo by Zoltan Tasi (unsplash.com/@zoltantasi).

The second is the challenge of making likable creatures that are so alien that readers have no way to connect to them.  For example, consider a creature that looks like a large boulder.  A creature that has a mouth but no eyes, ears or nose. A creature that thinks love and passion and excitement are all pointless. Does that sound appealing?

If an alien is not full of the same emotions and desires as humans, then it’s hard for us to connect.

A creature that has learned no form of communication other than to shove aside its brother as a signal that it is rolling too close.  A creature that enjoys listening to the vibrations of the stars as music and is tickled by gravitational waves, so it has no further need for entertainment or socializing.  If it is not interested in human pursuits, if an alien is not full of the same emotions and desires as humans, then it’s hard for us to connect. It’s hard for us to care.

So those are some of my theories.  Do you agree? Do you have examples you like that prove or disprove this?

Please post your comments below.

Be stellar!

Matthew Cross

Weird science that makes giant arthropods impossible

Some of Sci Fi’s most interesting aliens look like or share traits with Earth’s arthropods.  Arthropods include insects (like, ants), centipedes and millipedes, arachnids (like, spiders) and crustaceans (like, crabs and lobsters).  Think of the giant sandworms of Arrakis in Dune, the spider-like buggers of Ender’s Game, and the Bugs of Starship Troopers, which are very cool alien space bugs.  All of these aliens are human-size or larger.

But on Earth, physics and genetic history have kept arthropods much smaller than humans.  The largest arthropods alive are certain crabs and lobsters, and even the largest of these, the American Lobster, does not grow to 50 pounds.  Yes, that’s big for a lobster, but not exactly the match of a human in a gladiator ring or in a space battle.  It’s certainly not large enough to develop the large, complex brain needed for sentience.

Photo of crayfish. Crayfish exoskeletons form natural armor. Photo by Anton Ahlberg (https://unsplash.com
Crayfish exoskeletons form natural armor. Photo by Anton Ahlberg (https://unsplash.com

On Earth, arthropods developed exoskeletons (skeletons on their outsides), which provide great protection from enemies and allow the evolution of an amazing range of weapons and tools.  Consider the giant claws of a crab or the sting of a scorpion.  But exoskeletons restrict how large arthropods can afford to grow.  Molting — the process of replacing an exoskeleton as the animal grows — takes longer the larger the animal grows.  Some crabs take an entire month to climb out of their old skeleton and allow the new one to harden up.  Exoskeletal legs are also basically tubes filled with muscle and tissue.  If an arthropod grew to human size, the exoskeleton would not be strong enough to hold up the ‘pod’s weight.  And the arthropod’s muscles would not be strong enough to move the exoskeleton around.

Arthropods also evolved in a way that their cells get oxygen through gills, their skin, or tubes in their bodies, called tracheae, that open directly to the outside air.  Humans and other vertebrates have lungs and feed oxygen to the cells through the blood.  As ‘pods grow larger, it becomes harder and harder to get enough oxygen through their skin or tracheae to every cell.  A ‘pod as large as a human might easily suffocate.

As ‘pods grow larger, it becomes harder and harder to get enough oxygen to every cell.

But a ‘pod-like animal that evolved on another planet might not have those limits.  For example, we can imagine an alien “Pod” that evolved from simpler ancestors with both an internal and external skeleton.  Such creatures might have an internal skeleton in their arms and legs to support the weight of a large body.  But with a partial exoskeleton, the Pod might have a natural helmet for its head, giant claws, or possibly a scorpionlike tail.  With lungs instead of tracheae, the Pods could breathe like we do.  Finally, on an alien world with different elements in the rocks and soil, the Pods might evolve with exoskeletons made from lighter, stronger materials that would allow them to grow mighty armor and still move quickly.

Photo of two red crab claws clasping. Could a Pod with giant crablike claws evolve on some distant planet? 
Photo by Joshua Théophile (https://unsplash.com@nunchakouy).
Could a Pod with giant, crablike claws evolve on some distant planet?
Photo by Joshua Théophile (https://unsplash.com@nunchakouy).

Check out this great University of California at Berkeley website that explains the reasons that limit the size of arthropods on Earth.

Photo of bee.  Bees and wasps can fly AND sting. Photo by USGS (https://unsplash.com
Bees and wasps can fly and sting.
Photo by USGS (https://unsplash.com

Design a Pod

Let’s design our own alien Pod.

What two features that exist on Earth’s arthropods would you add to your Pod?  Would they make it a fearsome foe?  Would it have any weaknesses?

Please post your comments below.

Be stellar!

Matthew Cross

Subterranean Cities–Underground cities fill literature going back hundreds of years. Sci Fi writers dig into these ideas and unbury fresh new worlds to explore.

Colorful image of a cave--Subterranean Cities--Underground cities fill literature going back hundreds of years.  Sci Fi writers dig into these ideas and unbury fresh new worlds to explore.
Cover of Fortuna by Kristyn Merbeth

Today, I want to focus on cities built beneath the ground.  One is a fortress built beneath the frozen crust of a distant planet, and the other is a secret, centuries-old city far beneath New York City.

In Fortuna by Kristyn Merbeth, Corvus is a soldier on the planet Titan, a frozen planet divided by an eternal civil war.  Because of the severe cold and the constant fighting, Titans live in caves and in cities built beneath the ground.

In Chapter 18, Corvus is leaving the military and taking a train from Fort Sketa to a fortress city filled with civilians.

Empty train tunnel curving to the left
Photo by Claudia Soraya (unsplash.com/@claudiasoraya).

“The next morning, I wake early to head to the train for the sake of avoiding unwanted company.  The station is just below the surface, chillier than the lower levels of the building, and the ceiling trembles under the weight of activity in the hangar above.

 . . . .
“When I first arrived on Titan, underground rooms made me feel caged and nervous.  Especially so in places like this, where the ceiling occasionally shakes loose clouds of dust, and the rumble of trains along the tracks makes it feel like the whole building could collapse on top of me.  Over the years it’s become normal.  Now, for the first time in a long time, I wonder if it will feel strange to walk in the sunlight again.

 . . . .
“The underground fortress of Drev Dravaask is beautiful.  It’s warm enough that I take off my outer coat, and not overcrowded with people and buildings like the major cities of other planets.  There is a simple elegance to its architecture and a surprising kindness in its people.  They all nod or smile at me as I pass, or press their fingers to their hearts if they notice the [military] brand on my wrist.  I return the gesture without thought, drinking in the quiet.  It’s so peaceful here compared to the rest of Titan.  Neither the storms nor the war can touch this place. 

There is a simple elegance to its architecture and a surprising kindness in its people.


“Drev Dravaask has held its ground for over a century while cities around it crumbled.  The stability allows people to build lives here that do not revolve around war.  There are restaurants and shops, bars and inns, families that aren’t missing pieces.  Of course, there is also a huge military recruitment center near the heart of the city, and posters advertising the perks of service on every street corner, so it is not possible to forget entirely.”

Image of light shining into a blue pool of waterbeneath stalagtites

Sister Scorpia sees Drev Dravaask, the undground city on Titan, very differently

Corvus was born on the planet Titan and returned as an adult to serve his mandatory three-year tour as a soldier in Titan’s eternal civil war.  His sister, Scorpia, was born on the family’s spaceship, Fortuna, and has a very different impression of the underground Drev Dravaask.  After storing Fortuna in a cave hangar on the surface, Scorpia and her family take a slow, rusty elevator deep into the planet.

Man in hoodie with eyes closed standing under a hole in a concrete ceiling
Photo by Stephen O. Duntan (unsplash.com)

“The city of Drev Dravaask is carved into the earth beneath the surface of Titan, dark and damp caves forming homes and businesses and more.  The surface of the planet is too cold, too stormy; water freezes up there; and plants won’t grow, and people die slowly and numbly without realizing that they’re dying.  Down here, close to the hot springs that run beneath the surface, it’s a handful of degrees warmer.

“It would be easy to be miserable in a city like this, but the people of Drev Dravaask find pockets of happiness in their cold underground world.  As we head inward, a trio of soldiers sways past us arm in arm, belting a severely out-of-tune version of Titan’s planetary anthem.  A cluster of children giggle in an alleyway, finger-painting dirty words on the walls.  A hunched street vendor with a face full of battle scars hands a carefully wrapped meal to a gaunt teenager on the street corner.”

Gregor the Overlander finds a magical city of humans buried deep underground

In Gregor the Overlander by Suzanne Collins, Gregor and his baby sister, Boots, discover a mysterious land, called the Underland, filled with giant, talking rats, bats and cockroaches, that lies far beneath New York City.

View of a city full of lights seen through the mouth of a cavern

Gregor stumbles into the Underland and finds a city hidden deep beneath New York City

“There are but five known gateways to the Underland,” said Vikus.  “Two lead to the Dead Land, but you would never have survived those.  Two gateways open into the Waterway, but your clothing is quite dry.  You are alive, you are dry, from this I surmise you have fallen through the fifth gateway, the mouth of which I know to be in New York City.”

Vikus, a mysterious, bearded man with silver hair and violet eyes, leads Gregor to the human capital of the Underland.

“He followed Vikus down a tunnel lined with stone torches to a small arch filled with something dark and fluttery.  Gregor thought it might be more bats, but on closer inspection he saw it was a cloud of tiny black moths.  Was this what he had passed through when he stumbled into the stadium?

Photo of bat enfolded in its wings hanging upside down
Bat hanging upside down in a cave. Credit: Tine Evanic (unsplash.com/@tine999).

“Vikus gently slid his hand into the insects.  ‘These moths are a warning system peculiar to the Underland, I believe.  The moment their pattern of flight is disturbed by an intruder, every bat in the area discerns it.  I find it so perfect in its simplicity,’ he said.  Then he vanished into the moths.”

Welcome to the city of Regalia!

“Behind the curtain of wings, Gregor could hear his voice beckoning.  ‘Gregor the Overlander, welcome to the city of Regalia!’

 . . . .

“Gregor didn’t know what he’d expected.  Maybe stone houses, maybe caves—something primitive.  But there was nothing primitive about the magnificent city that spread before him.

“They stood on the edge of a valley filled with the most beautiful buildings he’d ever seen.  New York was known for its architecture, the elegant brownstones, the towering skyscrapers, the grand museums.  But compared with Regalia, it looked unplanned, like a place where someone had lined up a bunch of oddly shaped boxes in rows.

Photo of cathedral of gray stone with domed towers
Photo by Barb McMahon (unsplash.com/@barbmcmahon).

“The buildings here were all a lovely misty gray, which gave them a dreamlike quality.  They seemed to rise directly out of the rock as if they had been grown, not made by human hands.  Maybe they weren’t as tall as the skyscrapers Gregor knew by name, but they towered high above his head, some at least thirty stories and finished in artful peaks and turrets.  Thousands of torches were placed strategically so that a soft, dusky light illuminated the entire city.

“And the carvings . . . Gregor had seen cherubs and gargoyles on buildings before, but the walls of Regalia crawled with life.  People and cockroaches and fish and creatures Gregor had no name for fought and feasted and danced on every conceivable inch of space.”

Your favorite underground cities

Sci fi has lots more underground cities.  Which ones are your favorites?  Were they built on Earth, on other planets, or in other universes?  Were they built by humans, alien life, or ancient creatures long gone?

Please post your comments below.

Be stellar!

Matthew Cross