The National Railway Museum in York is the largest railway museum in the world, attracting almost 1 million visitors per year.

This network of narrow, medieval passages has the most delightful name.

These magnificent 240-year-old machines are considered distant ancestors of the computer.

This 170-year-old Swiss guesthouse built into the side of a mountain is best accessed by a cable car.

Rare wooden escalators lead deep down into an otherwise staggeringly monotonous tiled tunnel.

Artwork tucked within the trees greets visitors with surreal sonic experiences.

Hiding the longest subterranean river known in the world.

Each spring, a dreamlike carpet of bluebells overtakes the forest floor.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

A Volkswagen Beetle decorated with millions of beads connects Mexico's past and future.

Psychedelic murals coat the inside of a nondescript research library.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

A museum in the former home of Marxist revolutionary Leon Trotsky.

An elaborate Mayan city shrouded in alien conspiracy revealed the tomb of Pacal the Great.

An Aztec temple, the largest man-made pyramid in the world, sits buried in earth with a Spanish church set on top.

A church dedicated to the Mexican skeleton saint.

This space-age looking obelisk rises over a city in the rainforest, meant to resemble the local castaña tree.

This remarkably well-preserved Incan city managed to survive the conquistadores.

This abandoned fort is said to be the most haunted place in India, so much so that entry is prohibited after sunset.

In this mine all the gold you can carry may not be as sweet of a deal as it sounds.

The Incas turned this ancient Wari aqueduct into an imposing defensive gate.

A paradisical gorge with rapids, waterfalls, and wildlife whose raw beauty is the stuff of CGI movies.

The world's fifth tallest waterfall is a spectacular silver chute of water that cuts through the cloud forest in northern Peru.

The stones of this Incan wall complex fit together so well you couldn't fit a piece of paper between some of them.