An early work of the architect Álvaro Siza Vieira, these swimming pools blend into the beach.

An abandoned mine now resembles a post-apocalyptic landscape of derelict buildings and blood-red pools of water.

A stunning 18th-century site where pilgrims ascend by a series of punishing stairs only to return via funicular.

This gaping hole in the middle of a remote mountain lake looks like a portal to another dimension.

This Luxembourg cave is covered in cryptic looking marks left by mining activity.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

This noble mash-up in eastern Luxembourg is part Medieval, part Renaissance, all castle.

Once the local rulers had gone these enchanting ruins housed common folk in an almost real life fairy tale.

This tri-part waterfall is a little bit of fairytale beauty in the heart of Luxembourg's Little Switzerland.

A unique military outpost carved into a rocky outcrop in the English Channel.

A granite rock formation littered with various species of moss, lichen, and fern.

Before this bridge was built people had to wait for the ferryman, an annoyance that, the story has it, gave the town its name.

A sandstone block marks the alleged spot where the legendary writer was conceived.

On this romantic tidal island reachable only at low tide the tomb of a famous French writer overlooks the sea.

700 iron sculptures crammed into a Mediterranean park.

A 13th century fortified house built to defend the Duchy of Burgundy.

This crack in France's seaside cliffs once hid a sinister secret.

A snowy highland notorious for unexplained aircraft crashes is France's own Bermuda Triangle.

Immortalized by artists, this church incorporates a medieval lighthouse into its shoreside structure.

These ruins reveal the remarkably intact layout of a Roman marketplace.

The site of the first medieval crusade that pitted Christians against Christians.

Shattered columns and Egyptian pyramids outside of Paris.

18th century underground pilgrimage site, dedicated to a Saint that did something...

An abandoned nightclub has become a vibrant work of art.