Hundreds of secret cabinets built into the walls of legendary poisoner's private work room.

France's national museum of scientific and industrial instruments.

Site of a classic 19th-century physics experiment to prove the earth is rotating.

This demon atop the Notre-Dame de Paris looks utterly bored.

This former coal gasification plant found a curious second life as a popular public park.

The house where Lincoln drafted the Emancipation Proclamation.

A testament to Colorado’s rugged mining history sits against a backdrop of striking mountain scenery.

The mysterious “eyes of the Devil” dot a street in the occult center of Italy.

This sinister Baroque entryway could lead you to a terrible fate.

Despite their macabre past, these hooks are said to bring good luck to those who touch them.

Saint Borromeo often prayed in this austere crypt during the 16th century.

The remains of a historic plantation nestled in between a parking lot and the rental car return at Reagan National Airport.

A once-booming Mississippi River town with a history of racial violence is now eerie and mostly abandoned.

There is a strange little carving of a person seemingly crushed by a pillar behind the remains of St. Thomas Aquinas.

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

The huge golden reliquary of a testicle-smashing saint.

Historic medieval fortified city in southwest France.

This impressive chasm is one of the longest natural underground cavities in the world.

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."

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

France's most famous cemetery, with some of its most curious tombs.

The world's largest reflecting pool is just two centimeters deep.

Perhaps the world's only gas station inspired by a political scandal.