Nikola Tesla's former home contains an homage hidden from plain sight.

This historic building housed the surviving crew members of the Titanic, who were left destitute after the wreck.

This tower-tomb honors a president who only held office for a little over a month but dedicated his life to his country.

Mussolini gave Cincinnati a bronze statue of Romulus and Remus suckling at a wolf's teats.

A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

An ancient burial ground believed to have been used for ritual sacrifice.

An ancient Phoenician citadel once stood at the site where Queen Dido first landed, according to legend.

The best-preserved Roman small town in North Africa.

The largest and best-preserved Roman amphitheater in Africa was designed to seat 35,000 people.

This sculpture, residing in a quiet corner of a London park, honors the victims of 9/11.

The "beautiful" equation predicting the movement of all electromagnetic particles is engraved in front of Newton's tomb.

This ancient Egyptian obelisk still bears the wounds of World War I.

An architectural oddity hides in plain sight on this iconic London bridge.

A wonderfully eclectic Victorian aquarium lies in the basement of the Horniman Museum.

These official units of measurement—including chains and perches—lie hidden beneath tourists' feet in a popular London hub.

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

A Roman spa buried deep beneath the City of London.

A 2000-year-old Roman amphitheater lies just below Guildhall Yard.

Known for centuries as the famous Roman emperor's burial place, this monument is actually something else.

An ancient Roman temple first dedicated to an emperor's wife is now a church.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

This ancient market is often referred to as the oldest shopping mall in the world.

A forgotten "city of water" underneath the famous Trevi district.

This large, circular tomb is the final resting place of the first emperor of Rome.