This French castle is said to have once held the Holy Grail but is now a gorgeous mountaintop ruin.

A medieval military street hidden beneath a charming French fishing village.

A mosaic-tiled house built by graveyard sweeper Raymond Isidore.

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

These quaint French houses dangle precariously over a precipice.

This stunning French estate was so lavish that it landed its original owner in jail for the rest of his life.

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

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

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

An aluminum skeleton brings Chinese mythology to the French shore.

A well-preserved medieval village nested on a rocky outcrop and surrounded by a network of cliffs, natural bridges and canyons.

The fantastic architectural models of a French traveler.

This modern French ossuary contains the jumbled bones of 130,000 WWI soldiers.

Monsters and miniatures are held in equal esteem at this wondrous museum.

For hundreds of years, automatons moving to metallic music have been marking the passage of time.

Two small chapels housed inside an ancient tree.

The famous winding walk at Chartres is surrounded in mystery and myth.

A Gothic cathedral created from volcanic rocks.

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

Historic medieval fortified city in southwest France.

An icy lake tucked among jaw-dropping alpine panoramas.

The largest underground church in Europe.

A 14th century bridge built as a fortress, where the devil lurks on one of its towers.

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