One of the most easily accessible examples of the rare 1960s UFO houses.

An abandoned train station in Munich constructed for the 1972 Olympic games.

A statue of Vladimir Illyich Lenin guards this abandoned building in the "Forbidden City."

The scars of World War II are preserved on its walls.

One of the last remaining railway viaducts equipped with a transporter ferry.

This stone amphitheater was once part of Nazi Germany's plan to promote propaganda.

This concrete church spent a period of its history as a World War II bunker.

Constructed by forced laborers, this submarine pen is now a museum and war memorial.

Deep in the forest next to Augsburg are abandoned bunkers and bullet traps from the region's military past.

Hidden in the forest are the crumbling, graffiti-covered remains of the factory where most of Germany's explosives were produced during World War II.

The last remnants of a massive medieval wall that once encompassed the city of Berlin.

A ruined castle stands atop a hill surrounded by dragon lore.

Now overgrown, these anti-tank barriers from World War II are sometimes called "dragon's teeth."

The final resting place for a wealthy Roman family, this tomb might be the best preserved of its kind outside Italy.

Known simply as "The Hand," this famous public sculpture in Berlin was featured in a Depeche Mode music video.

An abandoned swimming pool decays on the outskirts of Berlin.

What started as a tongue-in-cheek shrine is now a full-blown museum celebrating "The Hoff" and his longtime love affair with Berlin.

The remains of a majestic house that was once stood in the crosshairs of the Irish Republican Army.

A former fortified tower now houses a collection of classic communications equipment.

A retired military stronghold on the rolling green coast of Donegal.

These moss-covered medieval ruins tower atop the smallest of Ireland's Aran Islands.

Ancient Bronze Age rampart that was used into the middle ages.

A Neolithic passage tomb said to have sheltered two legendary Irish lovers.

A massive Celtic cross secretly growing in an Irish forest.