Captain America, Sub-Mariner, and the Human Torch were all born in this art deco Manhattan masterpiece.

A former insane asylum despised by Nelly Bly and Charles Dickens is now fashionable apartments.

On this island, you suck away your garbage via an elaborate pneumatic tube system.

A crumbling hospital from the 1850s on Roosevelt Island.

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

Tour the oldest unrestored plantation house in America that is open to the public.

A modern ghost town whose inhabitants were driven away by the growth of nuclear power.

The Cape Cod house that whaling built.

This historic hotel invented the chocolate brownie.

This elaborate towering structure was once famed for its revolutionary height.

Renaissance hospital featuring a rotating door into which unwanted babies were dropped.

Venice's island of the dead.

The handiwork of a underdog clockmaker who solved an impossible problem for an Empire, and forever revolutionized seafaring.

The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

This stone gatehouse was once the entrance to a historic mountain resort, and it had a cameo in a cheesy cult horror movie.

Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

Carvings in Turkey's Marble Road may have directed ancient Romans to a hidden brothel.

Michael Jackson got Bad and Crocodile Dundee walked on heads in this iconic Brooklyn subway station.

This picturesque Umbrian city has a subterranean side that has long remained hidden.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

The first and only carousel with a lineup entirely of insects.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

The Atlantis of Cape Cod reemerges during the lowest of tides.