An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

Sacked by Vikings, blessed by William the Conqueror, dealt a fatal blow during the French Revolution—these ruins have seen it all.

Ancient paintings known as the "Sistine Chapel of Cave Art."

A museum on the history of Paris, including a set of Napoleon's toiletries, Proust's room, and relics of the Revolution.

This modern arts center is built around a gem of late-Baroque architecture.

This deceiving white sand beach gets its brilliant hue from the chemical discharge of a nearby factory.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

The only museum with its curator—and her pets—buried inside.

In a city that boasts four separate inclined cable railways, this is one of the busiest funicular lines in the world.

The oldest volcanology research center in the world.

This strange bovine gargoyle is said to have been put in as a passive aggressive form of revenge.

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

Renaissance hospital featuring a rotating door into which unwanted babies were dropped.

Five candy-colored villages on the Italian Riviera.

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

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

Rome’s legendary peephole vista is also a former Crusader stronghold.

The medieval castle built as headquarters for the Pope's secretive Knights Templar.

His "Lionheart" is entombed separately from the rest of his body.

Hamburgers are intensely proud of their tunnel beneath the river.

A portly statue of a golden boy commemorates an unusual cause of the Great Fire of London: the sin of gluttony.

The childhood home of Earth's alien chameleon is a humble Brixton flat.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.