A crumbling hospital from the 1850s on Roosevelt Island.

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

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

An alchemist's "magic door" stands in the middle of a Roman park.

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

The world's tallest doric column is this Ohio monument to a naval victory in the War of 1812.

Take a drunken tour inside the world's largest known geode.