An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

This bronze boy sits on one of Capri's rocky cliffs, waving at the passing boats.

This amazing abuela became a diehard metal fan late in life and an icon of Madrid's '80s rock scene.

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

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

The largest ice cave in the world is thought to be the entrance to hell according to Austrian legend.

This Nazi-built amphitheater was constructed on a sacred mountain site used by various German cults.

An industrial relic is now one of Europe's most staggering art spaces.

This cemetery features modernist statues as strange as its name.

Mountain where Jesus was first tempted by the Devil.

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

A beautiful but toxic fountain of mercury.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Iconic pyramid from famed British architect Norman Foster designed to represent all of the world's religious faiths.

A white Buddhist temple with a golden restroom.

Ruins of an early Roman Christian church dating back to the 4th to 5th centuries.

UNESCO-protected ancient burial ground.

An homage to the medieval rulers of Bulgaria.

An abandoned saucer-shaped monument in the Bulgarian mountains.

This once-grandiose behemoth of a monument from the socialist era now sits quiet and closed up.

This massive stone and steel monument remembers a century-old battle that cost thousands of lives and nearly destroyed the city.

Thanks to its heroic service during WWII this Soviet castle has been turned into a monument towered over by a brutalist titan.

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