A Swiss amusement park entirely dedicated to the theory of ancient astronauts.

A historic observatory precariously perched at the "Top of Europe."

A once-thriving hotel in the Swiss Alps couldn't compete with climate change.

Tombstones buried in overgrown grass mark the deceased occupants of this abandoned graveyard.

This soviet pilot's graveyard is filled with headstones made of airplane fins.

Several of these strange cone-shaped bunkers can still be seen around the former Nazi headquarters.

The ruined remains of the airport Claus von Stauffenberg departed in his failed attempt to kill Adolf Hitler.

This concrete residential area doubles as an open-air gallery.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

Ruins of a German Castle on top of a towering stone pillar.

Antarctica's bustling metropolis, originally established by Richard E. Byrd.

Featuring Zürich's only authentic 14th-century plague doctor's uniform!

This attraction was abandoned after the Chernobyl disaster.

One of the most poignant ruins of the Chernobyl nuclear disaster, the local football team's stadium has been quickly reclaimed by nature.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

The deepest hole drilled in the name of science, where evidence of Precambrian life was found.

A monument to the defenders of the Arctic in Murmansk, Russia.

A geological bull's-eye visible from outer space.

Once standing on solid ground, this slender beacon is a victim of the very shoreline it was charged with announcing.