A breathtaking canyon offers stunning views and frightful pathways through an ecological paradise.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

A Romanesque tower appears when water levels drop.

Stunning Roman aqueduct used for 1900 years and still standing.

Village situated on a narrow volcanic escarpment.

Abandoned Nazi train station turned underground astroparticle laboratory.

Giant eggs, walls of bread, and nightmare surreality mark the largest collection of works by Salvador Dalí.

Commonly acknowledged as the only public monument to the Devil himself.

This Navarrese cave's history of witchcraft and pagan ritual is not just embraced, but recreated each year.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

A gravity-defying "devil's bridge" that has a surprising architectural feature for its stability.

Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

Mountain where Jesus was first tempted by the Devil.

Hundreds of stone stairs and a winding medieval bridge connect this haunting Spanish island to the mainland.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

A museum dedicated to the Spanish occult in a town that was terrorized by the Inquisition.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

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

The final resting place to 300 Victorian-era pets hides inside the city park.

Overlooked by many, the two famous Scottish warriors guard the main gate of Edinburgh Castle.

This Scottish museum is the only one in the world to focus not on one religion but all of them.

The final resting place of soldiers' loyal canine companions.

Largest lake in Great Britain measured by surface area.

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.