The ridged layers that make up this river canyon represent Earth's geological history.

A pair of connected skyscrapers form this symbolic gateway.

This memorial park stands on the site of one of the largest mass executions of the Second World War.

A sinuous path among steep cliffs creates a stunning sight in southwestern Serbia.

Nikola Tesla's ashes are held in a golden sphere, surrounded by his works.

This 14th century castle withstood years of battle but is now sliding off the hills into the Danube.

Structure built from the skulls of vanquished foes.

Legends of treasure and spirits flow from this this fairy tale-like oasis.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

When a medieval fire claimed the original St. Stephen’s Cathedral, it sparked a pattern of unquenchable organ building.

This ancient ruined monastery has been destroyed by fire so many times that it seems like God hates it.

The tradition of open-air secondhand and antiquarian bookselling in Paris dates back to the Renaissance.

A Parisian cemetery where the elite and artistic are interred beneath an eccentric collection of tombs.

A favorite Paris bar for U.S. expats, including Gershwin, Hemingway, and James Bond.

Paris' linguistic guide to the international language of, yes, love.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

The world's longest and deepest train tunnel.

A little sculpture with a large wardrobe.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

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

This plaza is home to a number of works, including Montpellier‘s own Arc de Triomphe.

The lost Latin words were reconstructed using the holes from the nails that once pinned them in place.