Underneath this Byzantinian church lies a necropolis filled with ancient tombs and the ruins of previous churches.

A striking symbol of the Bulgarian capital.

"Unity, Creativity, Beauty."

A flamboyant five-story building in Bulgaria resembles a crawling snail.

"Holy Wisdom" overlooks the city that became its namesake.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

This unassuming alcove in London’s famous Tower Bridge once served to capture, store, and display dead bodies from the River Thames.

This pub boasts a curious history and may have inspired a Dickens character.

The first tunnel to be dug beneath a river, repurposed as an art and museum space.

Though it's not the largest, this one-kilometer outdoor market is reportedly the longest in Europe.

The last resting place of the famous Native American princess is marked by a haunting monument.

This star-shaped artillery fort protected the mouth of the Thames from the 16th century to the Second World War.

The biggest and deepest Cold War bunker open to the public can be found in southeast England.

Known as the "Fat Man of Maldon," Bright was a larger-than-life figure.

Constructed during the 7th century this is one of the oldest largely intact Christian churches in England.

This charming, narrow-gauge railway in the Thames Estuary is sometimes referred to as the "Train to Nowhere."

A perilous medieval road leading right into the sea.

This striking sculpture of Icarus honors Greece's fallen flyers.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

The oldest cemetery of modern-day Athens blends the modern and ancient worlds.

An ancient octagonal weather station named for the eight Greek gods of wind.

Gladiators once walked this ancient, subterranean passage.

A sharp sculpture made of thousands of pieces of jagged glass.

Where commuters walk through remnants of an ancient Greek necropolis.