One of only two commuter aerial tramways in the United States.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

Elevated freight railway turned wildly successful urban park.

A crumbling hospital from the 1850s on Roosevelt Island.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

The ruins of a Duke's bucolic dream, where camels once roamed alongside "Dutch" windmills and faux-Italian vineyards.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

A mechanized clock where a man fights off a dragon, crab, and rooster.

This historical swimming pool near Miami is emptied and refilled each day with naturally filtered water.