I'm a fan of subways. London is the classic of course. Munich is my personal favorite. But Washington D.C. has an extensive and very efficient system. Really modernistic:
And speaking of creepy, the first time I saw the entrance to the Dupont Circle station it gave me a vague sense of recognition and disquiet:
As we left the station on our final day in fact, there was some kind of malfunction in the PA system, so behind us I heard a harsh, guttural voice mumbling things I could not quite make out. A Morlock, almost for sure.
Head for the exit!