Museum dedicated to the terror regimes of Hungary.

This abandoned five-star hotel is now a five-star urban exploration destination.

A fantastic castle rumored to be the birthplace of King Arthur.

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

This crumbling, graffiti-covered mansion sits tantalizingly within reach of the proletariat who frequent a public park.

A 14th-century fortified keep showcases the masterpieces of an ingenious 20th-century clockmaker.

A visionary precursor to the Internet made of index cards.

Famously misunderstood wonder of the ancient world

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

Remains of Roman amphitheater hidden in a sleepy quarter of Paris.

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

Site of a classic 19th-century physics experiment to prove the earth is rotating.

This massive wooden building contains a giant Buddha, healing pillars, and tame deer wandering the grounds.

Devoted Buddhists can earn enlightenment in the next life by crawling through this symbolic nostril.

Largest graveyard in all of Japan surrounds a famous mausoleum.

A plaque marks the site directly below the mid-air detonation of the atomic bomb over Hiroshima.

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

This tumultuous Icelandic lava field looks so alien European researchers want to use it as a stand-in for Mars.

A sulfuric martian landscape that looks far better than it smells.

The abandoned Japanese amusement park once loomed as a dystopian Disneyland.

A garden in Lisbon filled with giant porcelain creatures.

This star-shaped military outpost is now simply trying to protect itself from neglect.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

Housing the groundbreaking maps and globes of Gerard Mercator.