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

This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

Amsterdam's former hotspot for public executions and dissections.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

A beautifully eclectic mix of architectural styles.

This modern French ossuary contains the jumbled bones of 130,000 WWI soldiers.

A giant bug impaled on a 75-foot-tall needle.

Each time a baby is born in Ghent, these streetlights flash in silent celebration.

Rare wooden escalators lead deep down into an otherwise staggeringly monotonous tiled tunnel.

This whimsical statue dumps water on its head to symbolize knowledge flowing into his brain. Or maybe booze.

The Belgian library displays burned books that were salvaged from the fires of both world wars.

This giant urban staircase was built to keep the city's brave fighting men from getting waylaid in the red light district.

A little sculpture with a large wardrobe.

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

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

The last bastion of Roman presence north of the Alps looms over a German town.

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

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

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

A dead saint, a deadly poison, and a mysterious holy ooze.

This curious building hides eclectic details like medieval gargoyles alongside naked angels and Art Nouveau mosaics.

The secret medieval communication system will whisk your words above the noise of the crowd.

Before there were doorbells this bronze ear was installed for visitors to announce their arrival.

The mark of the Devil's horns on a marble column in Milan.