The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

An "inside out" building in the historical center of Paris, featuring Europe’s largest modern art museum.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

This enormous "cloth of the conquest" depicts the Norman invasion of England in mind-blowing detail.

Remains of the artificial harbours invented for the Allied invasion of Normandy can still be seen at sea.

A memorial to the nearly 10,000 American soldiers laid to rest on the beaches of Normandy during WWII.

This place bears witness to the loss of many lives during WWII, and stands in stark contrast to the American Cemetery.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

France's most famous cemetery, with some of its most curious tombs.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

While not Turkey's deepest underground city, this subterranean redoubt is the largest.

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

A stunning mosque owes its design to an Ottoman ruler nicknamed "the Butcher."

This daunting 1st century fortress was purportedly the site of one of the most dramatic revolts of the Jewish-Roman wars.

The bluer than blue waters in these natural Israeli caves are reached via the world's steepest cable car.

The real-life site of Ichabod Crane's infamous gourd attack.

Oldest existing church in New York and the inspiration for Washington Irving's "The Legend of Sleepy Hollow."

There is only one place in the world where the corners of four nations come together.

The largest prehistoric ruins south of the Sahara, once a powerful center of international trade.

A section of the long chain that blocked enemy ships from entering Constantinople.

Quite possibly the oldest love poem known to humankind.

Ancient serpentine sacrifice holder that has stood the test of time.

This half-forgotten fortress was constructed by the Ottoman conqueror of Constantinople.