An unassuming secret door once led to a legendary watering hole.

The factory for the popular Dumbo location, the Greenpoint shop is a quiet gem.

The ballpark in "Pigtown" where the Brooklyn Dodgers made their name was replaced with a huge apartment complex.

The one-stop shop for all of your superhero (or evil arch-nemesis) needs.

This futuristic airport terminal was abandoned for decades before reopening as a hotel—with a vintage plane of its own parked out back.

On any given day this sprawling market houses literally tons of government-regulated gold, gems, and precious metals.

Formerly the world's largest, this Willy Wonka-esque contraption runs 24/7.

The famous facade of Grand Central Terminal hides a regulation tennis court, and it's not the first one.

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

A drawbridge named for a potentially intersex Polish national who fought alongside George Washington during the American Revolution, and an example of "Pulaski Red".

Nondescript building owned by ExxonMobil working on siphoning Greenpoint Oil Spill out of the ground.

A remnant from the golden age of aviation still in use today, Pan Am's Clipper service took off from this Art Deco gem.

A historic Black graveyard hidden in the parking lot of one of America's largest malls.

The ruins of an ancient Roman tomb hidden in the basement of a trendy clothing store.

This mystical orb covered in strange symbols is thought to have been used in ancient Greek magical rituals.

Where commuters walk through remnants of an ancient Greek necropolis.

Giant marble phalluses on the sacred island of antiquity.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

This legendary city has been a tourist attraction for centuries.

The hallucinogenic center of the ancient world.

This famous archeological mystery may be an ancient example of movable type.

This 15th-century island fortress later served as home to the executioners no one wanted to live near.

This symbolic piece of New Orleans architecture is also home to a few ghastly stories.