A German apartment building hosting as many trees as human occupants.

Dating back almost 400 years, the oldest public collection library in the United Kingdom was once the study hall of Karl Marx.

A Victorian Gothic masterpiece housing a world-class collection of rare books and manuscripts.

Once used to protect important Roman trade routes.

This alley off Edinburgh's Royal Mile contains remnants of the city's seedier history.

An artist's whimsical transformation of everyday objects.

Sprawled across the Great Hall ceiling are various constellations and images relating to the zodiac.

A familiar otherworldly creature guards this 12th-century Scottish abbey.

This classic restaurant features a gorgeous mirror-clad room.

Visitors can explore the role of mysticism throughout the ages inside this interactive museum of magic.

A narrow passage next to a cafe leads to a courtyard exploding with murals, tags, and paste-ups.

A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

This historical manor is complete with a magnificent garden.

A contemporary art installation housed within a Gothic cathedral.

The location of the Bridge of Death and the Gorge of Eternal Peril in "Monty Python and the Holy Grail."

This small town Texas cemetery is said to be the burial site of a UFO pilot who crashed in the 1800s.

Caves famous for the dragon-slaying saint who lived there.

An 800-year-old island castle in Guernsey's main harbor.

Underground hospital complex constructed by slave laborers during the German occupation of the Channel Islands.

An intricately decorated tiny place of worship.

Deep in the limestone cliffs of the Alabaster Coast, a German fortress built during World War II.

Burbling away in refrigerators are 105 sourdough starters from around the world.

Sharks, stingrays, and turtles swim in the pools at this former elementary school.

A statue of a mischievous raccoon towers over this city park.