The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

The most visited, and possibly most controversial, museum in Germany.

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

A museum marks and documents the site of the Titanic's launch.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

These mysterious Viking chess pieces spent centuries hidden on a remote Scottish island.

A statue of the legendary Celtic warrior queen who fought the Roman invaders stands in one of the cities she once destroyed.

London's smallest police station is barely the size of a phone booth.

This irregularly shaped sea fortress has defended not one but three different sovereign states.

It's a mystery why these remains were found with no traces of their bodies in sight.

All unmarked mute swans on the Thames are owned by the Queen per a tradition that began in the 12th century.

At just 51 feet and 10 inches long, it's the shortest street in England.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

Years of archaeology, just chillin' by the water cooler.

Famously misunderstood wonder of the ancient world

Every St. Andrews student knows to avoid this inscription for fear of a martyr's curse.

A sweet symbol marks the place where torturous executions were once carried out.

One of Ireland's most infamous prisons for rebels including men, women and children.

An interesting decoration on this historic site, this weathervane comes with as many legends as it does questions.

One of the indelible moments of the American Revolution took place at this location.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

The site of Paul Revere's historic two lantern warning.

The American Revolution was galvanized into serious action due to the tragic clash with British soldiers that occurred at this location.

The walls and streets of the ancient city are peppered with penises.