I always forget that Los Angeles has a subway at all, let alone the fact that it used to have a much more extensive one.

Parts of that old subway have sat, abandoned, beneath streets and buildings for decades. They've become part of the stratigraphy of the city, as humans do what humans have always done — build the new on top of the old and forget about what we covered up under there. It's no different than the way Rome was built, with the columns of old buildings serving as the foundations of new ones.

Back in May, blogger Gelatobaby got to go on a tour of one part L.A.'s lost subway, exploring a secret world exposed by renovations on a building that was once the city's main subway terminal. Her photos — including the one posted above — are amazing. Go check out the whole thing.