This mysterious Sardinian festival sees a horde of blank-faced equestrians compete for tin stars.

The titular "little arch" near this Italian resort is one of the most popular diving spots in the country.

Windblown rock formations in an ancient Roman quarry.

Ancient cave tombs known as the "houses of fairies."

The forbidden island of the Tuscan Archipelago may still contain buried treasure.

Ancient catacombs form the foundation for this Rococo orgy of a church.

Picturesque intersection of witchcraft and ancient Christianity.

An honorary saint of the people, Maria Adelaide became an incorrupt corpse, the clothes intact, exhaling “a strong scent of roses.”

The medieval castle built as headquarters for the Pope's secretive Knights Templar.

The quirky - and private - constructions of a secluded artist depict the house of God.

Whether they are bulls or pigs, these ancient animal sculptures are fascinating relics.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

This underground church is topped with a 500-foot cross that is seen by many as a beacon of fascist hubris.

One of the world's oldest universities houses an incredible collection of anatomical models, mummified body parts, and human bones.

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

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

Mysterious Spanish catacombs of unknown origins.

An outsider folly near Madrid.

The haunting concrete remains of a Nazi pebble crusher can still be found in this small French commune.

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

A massive base for the Nazis' most formidable weapon in the Atlantic.

Fighting the British and making game shows for over 150 years.

The world's largest reflecting pool is just two centimeters deep.

Do these monsters look familiar? The gargoyles on this church are all from pop culture.