This former maximum-security prison is creepy, sobering, and supposedly haunted.

History is hiding at the Morean Center for Clay.

You’ll feel like you’ve gone through the looking glass at this contemporary art museum filled with glass sculptures of every size, shape, and color.

The world's largest collection of autographed baseballs can be found at the St. Petersburg Museum of History.

A 19th-century cemetery device to ensure that the prematurely buried would be "saved by the bell."

Turning night into day in Victorian-era Austin to thwart a serial killer.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

The history of radiation is on safe display at the foot of a radiation science laboratory.

A lone cannonball remains lodged in the walls of the Hotel de Sens as a sober reminder of a revolution.

The video game-themed street art first popped up in the French city.

A mechanized clock where a man fights off a dragon, crab, and rooster.

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

An unusual number plate signifies the building's saucy past.

Walk upon the mementos of the dead in this Parisian courtyard paved with medieval tombstones.

The very center of Paris is surrounded by a bevy of strange good luck rituals.

Executions were once held near this beautiful 18th-century fountain.

Statue of death tucked in the University of Medicine courtyard.

A surrealist timepiece by the artist of melting clocks.

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

This mural painted by Keith Haring was done without payment as a gift to entertain the children at the Hôpital Necker.

Tombstones and enigmatic inscriptions hide within a vault beneath a popular London arts venue.

A mysterious shape catches the eye in this 16th-century painting.

The television series' iconic giant foot was borrowed from this classical painting.

The "beautiful" equation predicting the movement of all electromagnetic particles is engraved in front of Newton's tomb.