What looks like missing grout is actually an old pub's peephole.

Follow the original medieval paths that wind through this intriguing section of the city.

Where Agatha Christie mysteriously disappeared in 1926.

These 20-foot jaw bones honor a time when the leviathan bones were a sign that whalers survived the hunt.

The nearly 200-year-old folly has a secret spiral staircase hidden in one of its pillars.

These upturned herring boats make nifty storage sheds for fishing goods.

This enchanting Victorian estate was home to the world's first hydroelectric power generator.

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

Amsterdam's Red Light District leaves little to the imagination.

This historic Amsterdam bar used to accept sailor's monkeys as payment.

According to the Guanches, the aboriginal people of the Canary Islands, the king of evil lives inside this volcano.

Harry Potter once visited this massive limestone cliff, which was carved by an ancient glacial river.

These picturesque Hawaiian falls are home to a rare species of fish that uses a special sucker to climb up cliffs.

Partially collapsed lava tube and cave system complete with concert hall, underground pond, and unique albino crabs.

This lovely little burbling creek is actually a deadly waterway that has dragged down everyone who ever set foot in it.

This striking, two-toned confluence of rivers is visible from space.

The bar where "The Great Train Robbery" was planned was once a nexus of high society and low morals.

One of the oldest and certainly best preserved Cistercian abbeys still in existence.

This crumbling Death Valley mining complex was known for its use of giant, 20-mule team wagons.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

Fascinating town where normal life interfaces with the occult.

Abandoned silver mine strewn with wrecked and twisted structures.

Once an unstoppable source of gold and silver, this town came to a grinding stop when the groundwater proved deadly.