Finland's northernmost zoo is home to the country's only polar bears.

Roughly 17 million letters to Santa have found their way to this Arctic Circle post office.

If you visit Santa's village, you can get your passport stamped to show you crossed into the Arctic Circle.

This medieval Estonian tower provides access to a series of tunnels that have been home to soldiers, punks, and fine art.

A small island dotted with old, historic Finnish buildings.

A subterranean house of worship carved right out of the bedrock.

France's most famous cemetery, with some of its most curious tombs.

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

Monasteries on rock pillars, once accessible only by frayed ropes.

The ruins of this monumental city founded by the first Roman Emperor are strangely overlooked by most travelers.

Ancient Greek oracle of the dead.