What is it? Why, it's Coast City, of course, one of the DCU's fabulous fictionopolises. This empty shell doesn't really do it justice; you should have seen it when it was an enormous smoking crater!
The fictionopolis is one of the DCU's greatest tools. Although most of them have their origins in the Golden and Silver Ages, they were fairly indistinguishable from one another at the time (much like the heroes who made them home). In the Golden and Silver Ages, there was really no way to tell Gotham from Metropolis, unless there was someone you knew in the frame. Well... if it was dark out or there was a giant prop, you were probably in Gotham.
But as heroes in the post-Crisis DCU began to differ not just in powers, but in tone, philosophy, and personality, so did their cities.
First Gotham and Metropolis began to individualize themselves in ways complementary to their native heroes. Then when James Robinson invented Opal City to contextualize Starman, the phenomenon exploded. Nowadays, it is just as important to have a unique city to stage a hero's adventures in as it used to be to have a kid sidekick.
Coast City is a case in point. Even though it had been COMPLETELY BLASTED from the face of the planet, Geoff Johns found a way to bring it back to give Hal Jordan a fictionopolis of his own. So, too, Johns returned the Flash to a reconceived Keystone and invented St. Roch for Hawkman. A hero without his or her own city is just a player in someone else's story.
This why a "Contextualizing City" is part of our Dynastic Centerpiece model for building a mythos around a hero. Such cities must be fictionopolises; once you set a fictional superhero in a real city, it contradicts them instead of contextualizing them, and they're doomed. Poor Kyle Rayner is one such victim. It's also one of the things that has hampered Wonder Woman (Byrne's attempts with "Gateway City" did not succeed).
Lots of heroes have them already (e.g., Superman, Batman, Flash, Green Arrow, Atom, Hawkman, Green Lantern). Some desperately need them (e.g., Martian Manhunter, Black Canary).
Fortunately, there are some pre-existing cities still lying aroung in the Limbo section of the DCU Atlas, and in future posts we'll dust some of them off and advocate their return!