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

A massive marble foot is tucked away in a small alley near the Pantheon.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

Gods clash with machines in a power plant regenerated as a museum.

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

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

One of the most spectacular bridges in Spain spans a narrow chasm that divides the city of Ronda.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

The Roman city was the birthplace of various emperors and is home to one of the empire's most impressive architectural feats.

Spain's largest bullring offers a unique glimpse at architecture and history.

The final resting place of the great navigator, or maybe his brother.

The world's largest wooden structure.

The 3,600-year-old archeological sensation is considered to be the oldest representation of the cosmos.

Celebrating the works of a beloved Italian actor, known for such cult films as 'They Call Me Trinity' and 'Watch Out, We’re Mad!'

This monumental work of art symbolizes the coming together of a previously divided city.

A memorial in the Tiergarten is a reminder of the suffering inflicted on homosexuals by the Nazi regime.

The most visited, and possibly most controversial, museum in Germany.

A slice of central Asia in the middle of Berlin.

A 14th-century Serbian Orthodox church that was once converted into a mosque under the much-disfavored Ottoman Empire.