The Argonaute submarine was the French navy's pride and joy in the 1950's.

Once the tallest building in the world, this abandoned church is now a monument to the destruction of WWII.

A lone cannonball remains lodged in the walls of the Hotel de Sens as a sober reminder of a revolution.

This incredible stone temple is a monument to death, victory, and fantasy architecture.

When the rain falls, this drain system turns into a musical instrument.

This Dresden church was purposely rebuilt Protestant after being demolished in World War II.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

This doorless 20th-century elevator doesn't stop or slow down.

A Jenga-style cylindrical tower of books that appears to go on forever.

Macabre astrological automaton clock dating to the late 1400s.

The slender brass strip in Prague's Old Town Square was used to tell time from 1652 to 1918.

A 400-year-old mummified arm dangles from the ceiling of St. James the Greater, serving as a warning to thieves.

Baroque celebration of the end of the Great Plague of Vienna.

It's good luck to be mocked by this monkey.

A small but immensely extravagant palace built by the "Night King."

The fairy tale castle of the “fairy-tale king,” this was also the inspiration for Disney’s “Sleeping Beauty.”

A copy of the Statue of Liberty greets visitors to the birthplace of Auguste Bartholdi.

Shortest overhead power line in the world.

The largest bell in the world has been swinging high above a Cologne cathedral for almost a century.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

This 14th century wine cellar is home to the oldest barrel-stored wine in the world.

There has been an astronomical clock on this spot since the 14th century.

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

Sitting in the basement of a castle, the largest wine barrel in the world is bigger than most apartments.