This domed temple was built in a hidden cave mouth as a refuge for sinners seeking absolution.

A domed disco abandoned since the '70s now attracts artists and explorers under its unique roof.

A modern mechanical planetary system, part of a 10,000 year clock.

One of the highest mountain passes in Europe has been ranked among the best driving roads in the world.

Skulls and skeletons are omnipresent in this church dedicated to souls trapped in purgatory.

An abandoned quarry hides an open-air gallery of huge sculptures, some made from the rubble of 9/11.

This ultra-modern burial building would have stacked the dead like a giant filing cabinet.

This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

A star-shaped fortress town fort built in the geometric model of the Renaissance utopian city.

People have been living in the cave houses on this Italian hillside since the Neolithic era.

Crossing this suspension bridge feels like walking through the sky, a fitting tribute to the head of the Apollo program.

These medieval skyscrapers dominate the skyline of this small Tuscan town.

This abandoned Brutalist treehouse is a hidden architectural relic.

The giant skeleton sculpture is surprisingly well-traveled.

Eco-village hidden in the foothills of the Alps that created a massive system of psychedelic underground temples.

This quaint Italian town keeps losing ground as the sides of its plateau slowly erode.

Sitting on an Italian hilltop is this surreal fortress built by the mad inventor of electrohomeopathy.

An Italian hillside ghost town.

This 16th-century monastery has been turned into a surrealist architecture compound.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

Walk through a fairytale in Tuscany.

This picturesque Umbrian city has a subterranean side that has long remained hidden.

This medieval Italian town is a sheer (and beautiful) cliffside defense.

A hospital where antique dolls are given new life.