The highest pedestrian bridge in Singapore looks like a series of undulating waves rising between two public parks.

This stunningly massive housing complex is a go-to filming location for dystopian sci-fi cinema.

A quarry cum sculpture park where the works of art are chiseled into the very walls.

This mosque was based on Sub-Saharan Islamic architecture and created for the Senegalese Tirailleurs.

Abandoned blockhouses from Nazi Germany's Atlantic Wall erode into the sea on a French beach.

A colorful piece of contemporary art cheerfully clashes with Lyon's historical architecture.

A daring D-Day assault by U.S. Army Rangers is commemorated atop the high cliffs of this strategic point.

Bordered by forest on three sides and the ocean on the other, the Great Dune of Pilat is the highest sand dune in Europe.

France's high-tech, future-themed amusement park.

Tens of thousands of ancient rock carvings hidden in the heart of a French national park.

This otherworldly French waterfall looks like its waters have turned to stone.

Bits of architecture from a town destroyed in World War I now decorate this hotel garden.

An Orthodox church built by the Royal Family for the Russian community exiled to the French Riviera.

These crumbling Nazi artillery bunkers are now fair game for massive graffiti projects.

A 2017 crowdfunding campaign saved this historic castle from being destroyed.

This futuristic observatory at the top of the Pyrénées offers unrivaled views.

Trek into the depths of the cave where 17,000-year-old paintings exist alongside 400-year-old graffiti.

The 16th-century church was kept in its ruined state as a reminder of the casualties of World War I.

A chapel on a volcanic core, marking the end of a successful journey.

Sleep in a climate-controlled plastic bubble for the night.

This French castle is said to have once held the Holy Grail but is now a gorgeous mountaintop ruin.

A mosaic-tiled house built by graveyard sweeper Raymond Isidore.

The fantastic architectural models of a French traveler.

This stunning natural double arch, the largest in the Alps, went undiscovered until 2005.