What is the Thing?

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

See massive fossils that are over 200 million years old in northeastern Arizona.

Six ravens are kept captive (but well-fed) at the Tower of London to prevent the fall of the Crown.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

The former home of a mad diplomat is said to still be marked in bloody, arcane scrawls.

This city square is home to Amsterdam's oldest church and a statue honoring Dutch sex workers.

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

Two stone columns flank the grand Venice square, but there were supposed to be three.

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

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

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

The celebrated eyesore created by starry-eyed sweethearts.

A museum dedicated to one of Paris’s most famous residents, tucked into a corner of one of the city’s most famous squares.

The video game-themed street art first popped up in the French city.

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

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

Down a cobblestone alleyway is a museum dedicated to Romanticism, with a secret garden.

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

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

France's most famous cemetery, with some of its most curious tombs.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Send a postcard while vacationing with Satan.