A massive, secret marina for the Nazis' most formidable weapon in the Atlantic.

A colossal sculptural lion built by the same man who designed the Statue of Liberty.

A beautiful Victorian statue shows France's enduring love of the rhinoceros.

The birthplace of the ferocious William the Conqueror, this castle is awash in medieval history.

Trek into the depths of the cave where 17,000-year-old paintings exist alongside 400-year-old graffiti.

This ancient theater was once the home of fierce gladiatorial battles.

The world's tallest bridge is also possibly the most elegant.

The sunken structure looks like the victim of a catastrophic flood.

A medieval church with largest and oldest collection of Renaissance frescoes in France.

Beggars were miraculously "cured" of their fake ailments when they returned home to this 17th century Paris slum each night.

The largest underground church in Europe.

Lyon, France is home to two remarkably preserved Roman theaters, one dating back to 15 BCE.

The mental institution where Van Gogh created some of his most famous work now allows guests to walk in the artist's footsteps.

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

At Monet's beloved home you can still see the Japanese bridge, waterlilies, and weeping willows that were the subjects of some of his most iconic paintings.

A cave dwelling that was started by the Celts, expanded by monks, and finished by knights.

This salt marsh in Southern France is as pink as the flamingos that inhabit it.

An icy lake tucked among jaw-dropping alpine panoramas.

Ancient paintings known as the "Sistine Chapel of Cave Art."

The subterranean "lake" below the Paris opera house inspired the Phantom of the Opera's lair.

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

Dedicated to the man who saved hundreds of children from Nazi-occupied Czechoslovakia.

Created as a "model concentration camp" to hide Nazi atrocities from the international community, this former camp-ghetto now holds a museum and memorial honoring the lives lost within.

A mansion where wonders of Christmas are celebrated all year long.