Elevated freight railway turned wildly successful urban park.

A wall of chewing gum moonlights as collective art.

A museum dedicated to the history and exploration of both popular music and science fiction.

A giant Troll lurks under one of Seattle's oldest bridges.

This Viking gravestone carved in a rare runic style was dug up from a London churchyard.

This innovative steam machine was no doubt the most famous of the pioneer locomotives.

Hauled from the water's depths, Henry VIII's flagship is preserved in this capsule-shaped museum.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

Charles Babbage's proto-computer, painstakingly brought to life.

3,200-square-foot mural inside Dartmouth Library depicts the history of America with images of human sacrifice, ancient gods, and other unspeakable terrors.

An alleyway plaque is all that remains of the independent Texas' envoy that forgot to pay their rent for over a century.

Eighty million natural history specimens call this gargantuan museum home.

Hear the quietest sound from across the dome.

This staircase in a lush tropical grotto was built by enslaved laborers and renamed to honor Queen Victoria's role in ending slavery in the British Empire.

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

The hallucinogenic center of the ancient world.

The celebrated eyesore created by starry-eyed sweethearts.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Every year, the colorful murals of Montreal get a complete makeover.

One of the largest underground systems runs under Canada's largest urban center.

One of the Seven Wonders of the Modern World holds the world's tallest metal staircase.

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

One part antique store, one part curiosities hodge-podge.