Collapsing castle on the Hudson river was once the storage site of military surplus business.

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

A miniature rainforest is growing inside of a Midtown Manhattan office building.

Try not to get slimed in Tribeca.

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

A terrific purveyor of natural history objects and curios.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

This 1967 experiment in modular architecture was designed to be a new model for urban living.

One of Canada's most incredible rare book collections holds hundreds of thousands of gorgeous tomes that the general public can touch.

A book collector's dream, this Toronto bookstore has the world's first "Biblio-Mat," a random book vending machine.

Centuries before the modern seismograph, Armenian monks measured quakes with this tilting pillar.

A slab of sandstone covered with mysterious 1,000-year-old rock carvings from a vanished North American culture.

Little Red Lighthouse under the George Washington Bridge.

Lady Liberty's first beacon of enlightenment is now displayed in a museum near the statue.

A 600-year-old mini shrine guarded by a sword-wielding knight hides in a crumbling cliff face.

A deserted island in southwest Japan that once sheltered persecuted Christians.

Reaching the "Church in the Sky" requires scaling the cliff face of a sandstone pinnacle with a 650-foot drop.

The world’s oldest and biggest bookstore stocking only mystery, crime fiction, espionage, and thrillers.

Though its celestial ceiling is impressive, the true star is the vast collection of French books.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

This Niagara Falls tourist trap is a world bright with neon and curiosities that will inspire love, hate, or a mixture of both.

Canada's oldest sugar maple has been growing since around 1500.

A hidden treasure of an abandoned city lies deep in the jungles of Campeche, Mexico.

The ruins of an ancient Mayan city, beautifully preserved and only accessible by boat.