One of the first self-sufficient Arcologies in existence, the DIA stretches for miles underground. It began as a research and military facility capable of airing covert flights. Now it is the foremost regional hub for space travel and Suborbital Passenger Drones.
After the United States of America was reformed as New American Republic, the DIA has been expanded upward to become the foremost Air & Space port in North America. It boasts large-capacity Space Elevators.
Its original levels were built during The Amero-Soviet Cold War and reflect Arco-Engineering ("Welfare Arcology") principles, for better or for worse. Oh well, that's for poor people.
The upper levels follow Marxist Arcology principles limited to the Cog Class, effectively a form of Bourgeois Marxism in practice.