This futuristic observatory at the top of the Pyrénées offers unrivaled views.

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

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

Hundreds of prehistoric stones, arranged in perfect lines in a French field.

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

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

This stunning natural double arch, the largest in the Alps, went undiscovered until 2005.

These quaint French houses dangle precariously over a precipice.

A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."

This historic island prison holds one of the dungeons from the Count of Monte Cristo even though it is a work of fiction.

Sleep in a climate-controlled plastic bubble for the night.

The largest underground church in Europe.

Hundreds of hidden passageways weave through the old quarters of Lyon.

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

This modest marker near Notre Dame identifies the very center of Paris.

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