Largest lake in Great Britain measured by surface area.

This 17th-century street hidden beneath Edinburgh was once a breeding ground for the black death.

This historic Benedictine monastery brews a booze so toxic that it has often been blamed almost singularly for Scottish hooliganism.

These medieval tunnels provided water to the city above through centuries of civil war and plague.

This one has sailed five times as far as Sir Francis Drake's famous ship.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

Mysteriously stacked storefront paths give this medieval British town an iconic style like none other.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

God's Saharan sandbox of wrath.

Traditional 11th-century outdoor tannery.

The other side is actually green.

A fortified city, home to a remaining population of five families

One of the most spectacular canyons in the world.

Single runway interrupted by a busy road that cuts across its middle.

Founded as a refugee camp, now a popular tourist spot.

An abstract monument to a symphonic composer.

A subterranean house of worship carved right out of the bedrock.

A little sculpture with a large wardrobe.

Climb inside an iron crystal magnified 165 billion times its normal size.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

Ripped apart by a bomb in 1993, the shell of Pablo Escobar's infamous vacation house still stands.

Cathedral carved out of salt, located a mile below the Earth's surface.

A 10 million-ton rock once worshiped by the Tahamies Indians, accessed by an astounding staircase.

A dangling church built over a Colombian gorge.