The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

In the days before house numbers, these colorful signs held clues about various buildings' purposes.

An ancient passage filled with stalls selling used books, once frequented by Vincent Van Gogh.

Lava stone structures possibly dating back to the 19th century may have been a stopping point for voyagers between ancient Egypt and the Mayan Civilization.

According to the Guanches, the aboriginal people of the Canary Islands, the king of evil lives inside this volcano.

Graffiti from the 16th and 17th centuries cover the walls of this part of the Tower of London.

This secluded walkway overlooks a magnificently wild London green space.

Legends say that this Art Deco apartment building almost became Hitler's British headquarters.

This hidden green space is the city's second largest conservatory.

Catacombs turned marketplace.

The majority of the museum's large collection is held in a storage space open to the public a few times a year.

In Twickenham sits a small whitewashed castle that inspired Mary Shelley's 'Frankenstein.'

Of the many chalices in the running for the Holy Grail, this one in Valencia Cathedral sure looks the part.

Originally used to sell brandy, the bull-shaped billboard became an iconic symbol of Spain.

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

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.

The world's largest wooden structure.

This stately council chamber hasn't changed since 1545.

A hidden church in a hidden courtyard tells the story of the Miracle of Amsterdam.

Amsterdam's former hotspot for public executions and dissections.

Rotterdammers' dirty minds gave this Santa a dirty nickname and cursed it to a life of wandering.

The place where Czar Peter I of Russia resided in 1697 during his Grand Embassy.

This fairy tale forest hides scenes from some of the more obscure and bizarre Western nursery stories.