London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

An alleyway plaque is all that remains of the independent Texas' envoy that forgot to pay their rent for over a century.

Northern Ireland's Brobdingnagian stepping stones.

The ruins of this medieval castle in Northern Ireland have inspired artists from C.S. Lewis to Led Zeppelin.

This short bridge is the only thing connecting a tiny Irish island to the mainland.

An Irish cemetery filled with victims of political strife and violent conflict, including the grave of Bobby Sands.

A palatial former bank building now houses what may be the poshest art venue (and former Tesco) in Belfast.

Belfast's namesake river still winds below the city center, hidden from sight.

This religious complex carved into a cliff is steeped in legends of miraculous stags and the Holy Grail.

Cliffside houses provide a spectacular view from their perch above the valley.

12th-century holy complex shares land with a natural park full of heavenly waterfalls and raptors.

Translating as "The Jump of the Girlfriend," this stunning waterfall has a tragic legend behind it.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

Among the oldest structures in Madrid, these Moorish walls once guarded the medieval city of Mayrit.

A towering monument in Spain has proven to be more labor-intensive than initially planned.

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

An ancient Egyptian temple in the middle of Madrid, Spain.

The future of roadside attractions is this sci-fi soda mecca that is home to a 66-foot tall neon pop bottle.

Along the historic Mother Road is an old gas station with a secret counterfeiting past.

This small piece of railroad history sits behind the parking lot of a chain grocery store.

The scene of one of the darkest moments in American labor history has been left essentially untouched since the tragedy.

A face emerges from the landscape when seen from the air.

"...I guess that was your accomplice in the wood chipper?"

The largest self-built castle in the U.S., six decades in the making.