One of the most spectacular bridges in Spain spans a narrow chasm that divides the city of Ronda.

The little-known second castle that William the Conqueror built in York.

An engineering error ensured this cavernous 350-foot-long subterranean thoroughfare was never used as intended.

Amidst towering office buildings, a local pub lives inside Sheffield’s oldest surviving domestic building.

A medieval wash house where people washed clothes in a river allegedly formed by the tears of a mourning nymph.

The world's most active stratovolcano is almost always erupting.

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

A local museum honors the overlooked discoveries of Mary Anning, one of the first professional fossil hunters.

Overlooking the burial ground is a tower designed to prevent thieves from snatching the recently deceased.

This Birnam-based garden honors the legacy of 19th-century children’s book author Beatrix Potter.

Touching this 18th-century Scottish philosopher’s toe allegedly conjures good fortune.

This beautiful deer park was built so King Charles I and his court could go hunting while escaping a deadly plague outbreak.

The remnants of a creative early method of wildfire prevention.

The fierce beast perches atop a pedestal marking where the historic City of London gates once stood.

This otherwise ordinary close on the Royal Mile constituted the end of the world for Edinburgh’s poorest residents.

A measuring mishap led to these artificial stone ladies losing their stomachs.

A monument to the one-armed geologist who led the first documented expeditions through the Grand Canyon.

Cornish legend says these ancient circles were people turned to stone for playing hurling on a Sunday.

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

This network of narrow, medieval passages has the most delightful name.

One of the earliest large-scale "hyper" roofs in the U.K. is now a derelict roadside attraction.

This ancient altar emerges from the thick forests to reveal the mysteries of Etruscan sacrificial rituals.

The blinking light atop the iconic landmark has been sending secret messages for decades.

Brightly colored 30-foot-tall totems light up the desert sky just outside Las Vegas.