A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

Bloodstains can still be seen in this medieval church where two medics saved lives on D-Day.

There are hundreds of secret WWII bases hidden in British forests. Built to fight a Nazi invasion, they remained unknown for decades.

The lighthouse is on a island which is connected to another island, which is connected to another island, which is connected to one of the largest islands in the world.

This Welsh village gave itself a ridiculous name in a publicity stunt a century ahead of its time.

The stately remains of Llywelyn the Great's mighty fortress.

The longest and tallest aqueduct in Britain can actually be sailed across.

These precariously placed ruins harken back to a 13th-century castle.

Remains of Roman amphitheater hidden in a sleepy quarter of Paris.

The remains of the medieval wall that once surrounded Paris with ties to the construction of the Louvre.

The approximate spot where the last Grand Master of the Knights Templar was put to death.

The narrowest street in Paris.

"In the Dark" Restaurant in Paris offers dinner in complete darkness.

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

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

Fortified medieval tower house with lovely roof garden.

Next to the Leaning Tower of Pisa is a cemetery home to ancient sarcophagi and disturbing murals.

In an area where the remnants of WWI are discovered on a regular basis this preserved frontline trench may be the most amazing.

The earliest known map to show America, discovered by accident at a Paris bookshop.

A window into a long-lost world, these colorful tiles advertise a long-defunct range of purgative teas, harmless smokables, and diarrhea cures.

Remains of the lost church hide beneath this Spanish Parliament building.

The magic of Spanish aviation housed under one roof.

A lush indoor jungle fills this bustling Madrid transportation hub.

A reproduction of the famous prehistoric cave paintings is hidden underground at the National Archaeological Museum.