This small Bavarian graveyard is filled with empty graves for German soldiers lost during the World Wars.

Soaring over 6,000 feet in the Bavarian Alps, this beer garden was once Hitler's 50th birthday present.

Dress up like a miner and take a slide into the disco-lit depths of this once foundational salt mine.

A tiny church on a man-made island in the Adriatic.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

A curious little museum dedicated to the furry feline in the cat haven that is Old Town Kotor.

The complex has been abandoned since the Croatian War of Independence, barring a stint as a set for 'Game of Thrones.'

Bridge that died in war and was resurected.

A former bank seized as a sniper vantage point during the Bosnian War is now a secret graffiti art gallery.

The sad remains of a monument to martial arts legend and movie star Bruce Lee—in the middle of Balkans.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

A musical instrument played by the sea.

This former estate of a fascist leader is now a burnt out ruin leading to a system of secret tunnels.

This scale model of our solar system hid in plain sight for years before a physics team sought out all the planets.

Where the lovelorn find a home for their sentimental keepsakes.

A World War II evacuation tunnel turned into a history display of Croatian state and people.

A pair of connected skyscrapers form this symbolic gateway.

A small memorial to a deadly night in Serbia that shook the world before it was swept under the rug.

Destroyed Serbian army headquarters sits half crumbled in a largely revitalized Belgrade.

Ireland's only German military cemetery holds the remains of a spy who was moved there under the cover of darkness.

This Bronze Age tomb is the centerpiece of a clearing within a beautiful Irish forest.

One of Ireland's most infamous prisons for rebels including men, women and children.

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

A mysterious plaque to the even more mysterious "Fr. Pat Noise," killed in "suspicious circumstances."