Remember in the movie of The Lord of the Rings: The Return of the King, when Gollum leads Frodo and Sam to the Pass of Cirith Ungol, which turns out to be a worn staircase of stone that seems to go straight up, more a miles-long ladder than a stair? I never figured that anything like that actually existed, but the other day -- and forgive me, I can't remember where I saw this first linked -- I learned of the existence of the Ha'iku Stairs in Hawaii.
These stairs were built to service a low-frequency radio antenna during World War II. They've fallen into disrepair over the years, but they're still there and accessible, if obviously dangerous. The wonders of this world are innumerable, aren't they?