Where It All Goes Down
WICKED Headquarters
The headquarters of WICKED is where we start the novel and just about where we end it, too. In the beginning, we mostly get the idea that the inside of WICKED's headquarters is just one giant maze, which is probably an allusion to the Maze from Book One. There are hidden rooms and tons of twists and turns and double doors—the place just perfectly fits all that is WICKED.
But at the end of the book, Thomas has to enter WICKED's headquarters from the outside, and that's where we get the full effect of the setting. Thomas feels like he's in a "brand-new world—a place untouched by disease" when he notices how the "air was crisp and cool" (57.2). Plus, just take a look at how Dashner describes the place:
Craggy stones of all sizes dotted the land, which sloped toward a sudden drop-off—a huge cliff. Beyond that lay the ocean, its deep blue ending on the horizon, where in a sharp line it changed to the light blue of the brilliant sky. And resting on the edge of the cliff, about a mile ahead of him, was WICKED's headquarters. (57.5)
Rugged landscape? Check.
Giant cliff with buildings on the edge? Check
Beautiful ocean? Check
Come on, how much more menacing and ominous could WICKED possibly get without looking the castle of the Wicked Witch of the West?
Denver
Unfortunately, Denver isn't the same Denver we know and love today. People aren't flocking to Broncos games, having a grand old time; in fact, people aren't really people in Denver. The Flare is running rampant throughout the world, and though Denver is an area that seems to be managing the outbreak pretty well, it's still doomed to be destroyed. People wear gas masks and hold rags up to their mouths and noses as they walk through the street, and no one seems to want to make eye contact.
To make matters worse, the Crank rebellion seems to start to take over the city as the novel advances. When they arrive, Thomas and his friends are met with a decent amount of safety, but as they leave the city, it's being overrun with Cranks.
Denver is a good miniature image of the apocalypse in The Death Cure. It was once one of the only "safe" places to be in the planet, but even so, it hasn't been able to shield itself from the inevitable downfall of civilization.
Sorry, Broncos fans, but there won't be any 65-yard field goals with Cranks running around the streets.
Paradise
When the Trials are finally over and Thomas reaches his final destination, he gets what he really deserves (sort of): a paradise to live in. We only get one chapter of the Immunes relishing in this place's glory, but from how Thomas sees it, we can only imagine just the most beautiful place ever:
Lush and green and full of vibrant life... The two hundred or so people they'd rescued wandered the area, some of them actually running and jumping. To his right the hill descended into a valley of towering trees that seemed to stretched for miles, ending in a wall of rocky mountains that jutted toward the cloudless blue sky. To his left, the grassy field slowly became scrub brush and then sand. And then the ocean, its waves big and dark and white-tipped as they crashed onto a beach. (73.8)
Basically, it's the typical tropical paradise that we'd imagine at the end of a journey such as Thomas's. It's ironic, in a way, though, that all these kids gets get to go to paradise (kind of another word for heaven) while everyone else in the world bites the dust. But think of it this way: Thomas and friends are—we assume—going to start civilization anew, so in a way, it's appropriate that they're in a sort of new Garden of Eden, the place—at least in the Judeo-Christian tradition—where civilization started the first time around.