This blowhole is supposedly caused by a trapped monster.

A once-glowing grotto at the bottom of Waikapalae Wet Cave.

This former luxury resort in Kaua'i is now an abandoned relic.

Carvings in Turkey's Marble Road may have directed ancient Romans to a hidden brothel.

Giant marble phalluses on the sacred island of antiquity.

The hallucinogenic center of the ancient world.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

This memorial commemorating fallen Swiss Guards of the French Revolution has been called the saddest stone in the world.

One hundred years ago this small house in downtown Zürich became the birthplace of the Dada movement.

The celebrated eyesore created by starry-eyed sweethearts.

135 bronze medallions mark a French meridian line which once rivaled the hotshot Greenwich timeline.

The yawning maw of this pagan visage is said to bite off the hands of liars.

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

The famous sculptor left his mark on this Italian wall in an internationally protected example of street art.

The most loyal of little dogs, or a Victorian era publicity stunt?

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

Created by one of England's most prolific labyrinth designers, inspired by Bath city history.

A fantastic castle rumored to be the birthplace of King Arthur.

Used as an example in one of the first dictionary entries for "museum" in 1706.

A theatre built to house the rowdy Oxford graduation ceremonies became the stage for a debate about God's existence.

One of Europe's oldest libraries.

Hidden in plain sight, this creepy sculpture watches from above.

This 11th century tower is said to be the oldest building in Oxford.

A statue marks the exact spot where The Boy Who Never Grows Up made his first literary appearance.