The first museum in the United States dedicated entirely to posters.

A former insane asylum despised by Nelly Bly and Charles Dickens is now fashionable apartments.

A way to take your secrets to someone else's grave.

This empty Victorian manse on Staten Island is said to be haunted but is actually a real life crime scene.

One of the last Jazz Age "Wonder Theaters" in New York City.

Tucked in a nondescript downtown Brooklyn mall is a bar containing a remarkable turn of the century anatomical wax collection last seen in 1920s Berlin.

The oldest surviving synagogue in New York City is now a soaring art space.

A Victorian cemetery in the heart of Brooklyn remains a popular mecca of morbid curiosity.

Just your average Marie Antoinette–themed speakeasy in an abandoned 19th-century subway tunnel.

Elevated freight railway turned wildly successful urban park.

Inside this library, the history of Los Angeles is retold through a mural.

This museum in the tower of the oldest church in Gdańsk, is home to centuries-old time-keeping devices and the world's first pulsar clock.

Built to transport German U-boats through the never-completed Masurian Canal, the locks near this Polish village are now home to a rope course.

The relics are stored in a silver reliquary, where they can be seen through glass.

In northeastern Poland, the ruins of a massive granary overlook the Narew River.

This picturesque castle in Poland has a rich history, including a legend that ties it to lost Incan treasures.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

Dubbed "Wistom" by locals, this abandoned factory is an urban explorer's dream.

This grubby wall is said to be one of the Earth's esoteric energy centers.

This enormous 32-foot painting depicts Poland's greatest medieval battle in glorious detail.

Modern art commemorates one of the first military actions of World War II.

A merchant court dedicated to the fictitious King Arthur is heavily adorned with bizarre Renaissance art.

This antique thermometer honors the creator of the first universal temperature scale.