1513 Turkish world map, full of European state secrets and snarky commentary.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

A small etching on the white marble parapet was written in runic script by a Viking mercenary.

The ornate miniature mansions were built for Istanbul's feathered residents.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

The giant statue and its model solar system honor the native Pole who declared that the Earth revolves around the Sun.

The mysterious large white cross visible from the runway is a memorial to a massacre during Spanish Civil War.

Replicas of fossils unearthed during renovation work reveal how this area would have looked millions of years ago.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

This stunning iron gate designed by Modernist architect Antoni Gaudí is filled with mythic symbolism.

The world's largest wooden structure.

Mountain where Jesus was first tempted by the Devil.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Hidden beneath a beautiful overlook you’ll find the history of the city depicted in comic strip format next to a pay toilet.

This wild explosion of color on a disused water tower tells the whimsical tale of a curious puffin.

A statue in the center of Dublin dedicated to one of their favorite sons of rock & roll.

The house where the writer spent his formative years.

The tallest church in Mechelen might have been the tallest in the world if not for a lack of funds.

A solid steel plane designed to catch fire over and over again.

The world's largest bicycle shelter can hold more than 12,500 two-wheelers.

Yup, that's a 330-foot yacht passing over the highway.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.