One of the many reasons I'm fond of DC is the subway system. It makes getting around town one hell of a lot easier and there's just so many photo opportunities down there. Louisville doesn't have a subway, it'd probably just flood if it did, so I had to take advantage of my visit to get some shots.
I've tried taking photos of the Metro before but never had a wide angle or a lens that had a low enough f stop that I could shoot halfway decently down there.
If brutalism and Big Brother had a bastard child it would be a Metro station. Speakers befitting a Two Minutes Hate demand you surveil and snitch on other travelers, accompanied by the tromping of transit cops. Then again, that's the case most any way you travel in the USA these days.
Since tall buildings are called skyscrapers, does that make subterranean structures groundscrapers?
Michael Wolf did a series of photos, Tokyo Compression that I'm rather fond of. There's nowhere near as many people riding the Metro but it's still a lovely bit of inspiration.