A comic book store that puts the marvel back in marvellous.

Scattered throughout London are ancient remnants of the city's former bounding wall.

The largest of London's subterranean rivers and once a mad, bad center of London life.

These quaint French houses dangle precariously over a precipice.

A colorful piece of contemporary art cheerfully clashes with Lyon's historical architecture.

Hundreds of hidden passageways weave through the old quarters of Lyon.

For hundreds of years, automatons moving to metallic music have been marking the passage of time.

Over 50 exquisite hand-painted Renaissance maps decorate a Medici storage room.

Breathtaking and huge 430 year old maps of Italy.

An incarceration museum on the spot of possibly the oldest prison in England.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

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

Jesus' footprints and the first catacombs in the world.

Harlequin costumes, signed scripts, and armor-wearing puppets.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

A sprawling collection of books and manuscripts about ancient Greece that would have put their famed libraries to shame.

Where commuters walk through remnants of an ancient Greek necropolis.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

Seventeen oak trees sprout from the roof and walls of this tiny chapel without any visual evidence of roots.

Monasteries on rock pillars, once accessible only by frayed ropes.

A cave network located at the southernmost tip of mainland Greece was once believed to be an entrance to Hades.

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

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

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