Ancient ruins hidden underneath a modern luxury hotel.

Architectureal fantasy quarter of Rome.

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

An alchemist's "magic door" stands in the middle of a Roman park.

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

A small cell adjacent to this church was once the bedroom for a renowned saint.

Plaques on its facade commemorate the Tiber's most destructive deluges.

A statue representing a lost Roman profession that was vandalized for centuries.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

Brass cobblestones mark the places where individual Holocaust victims were taken from their homes.

The "Greatest Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

This ancient Roman arch misled treasure hunters for centuries.

St. Francesca Romana, patron saint of drivers, resides in the church she founded.

A collection of objects supposedly singed by the hands of souls in purgatory.

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

The spot where the fascist dictator made some of his most famous speeches including declaring war on Britain and France.

The final resting place of the poets Shelley and Keats.

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

Ancient Egyptian wigs, South American feather headdresses, a bounty of anthropological artifacts in Oxford.

J.R.R Tolkien, C.S. Lewis, and other "Inklings" met at the Oxford pub to discuss the now legendary fantasy stories they were writing.

The fantastic charm of England's oldest botanical garden has made it a place of writerly inspiration for centuries.

Hidden in plain sight, this creepy sculpture watches from above.

The Cambridge pub where Francis Crick announced that he and James Watson had discovered the DNA double-helix.

A complicated contraption for telling time by the moon.