Museum preserving torture methods from the past.

The eclectic observatory castle of a 19th-century astronomer and explorer.

A neighborhood church's unusual abstract stained glass was the final project of avant-garde artist Jean Cocteau.

Exquisite examples prehistoric bas-relief carvings.

100-windowed castle turned art gallery, built by one dedicated mason.

The opulent home that inspired Tintin's Marlinspike Hall and the adventures within.

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

Legend has it this 11th-century castle was paid a visit from the devil.

These medieval ruins have survived since the 12th century, even providing shelter from the Nazis.

This otherworldly French waterfall looks like its waters have turned to stone.

The world's most famous cheese caves.

The spiral staircase hidden inside this giant Parisian column was likely built for Catherine de Medici's astrologer.

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.

If they push on just the right spot, even the weakest person can move this titanic boulder.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

There has been an astronomical clock on this spot since the 14th century.

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

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

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

These quaint French houses dangle precariously over a precipice.

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

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

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

An icy lake tucked among jaw-dropping alpine panoramas.