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

The Pope’s secret escape route.

The yawning maw of this pagan visage is said to bite off the hands of liars.

The best preserved Paleochristian basilica in Rome hides a number of oddities and secrets.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

If you want to talk to the Pope you will have to stare down this surreal vision of Jesus rising from a nuclear hell.

This equestrian statue of Constantine the Great has been the subject of criticism for centuries.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

Breathtaking and huge 430 year old maps of Italy.

This Manchester laundromat is hiding something.

A mysterious, weather-beaten bus lies on the coast of Harris, enticing the curious to investigate.

The sign marks one of the endpoints to mainland Britain's longest overland travel route.

Amazing and mysterious Neolithic settlement on Scotland's Orkney Islands.

On a remote island, legend has it that a fiddler and his wife were turned to stone.

A remarkably well preserved tower dating all the way back to the Iron Age.

This picturesque archeological site looks like it was pulled straight from a fantasy novel.

The remains of the wrecked steam trawler can be found on the beach at low tide.

Northern Ireland's Brobdingnagian stepping stones.

This short bridge is the only thing connecting a tiny Irish island to the mainland.

The "Black Arch" guards the entrance to the picturesque Glens of Antrim.

A museum marks and documents the site of the Titanic's launch.

A boulder in the Churchyard of Down Cathedral marks the legendary burial place of "The Apostle of Ireland."

A medieval abbey featured on 'Game of Thrones' that dates back to the 12th-century.