The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

World's first "penitentiary," meant to be humane, drove men insane.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

A complex, nine-layer maze on the grounds of a Venetian doge's playground.

The oldest of Venice's plague quarantine stations, designed to keep the medieval city safe from disease.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

A village on the east coast of England that has almost completely eroded into the North Sea.

Venice's "Island of the Mad."

A small island less than half a mile from Venice is a forbidden island with a dark and twisted past.

Venice's island of the dead.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

Mysterious craters may have been home to an ancient cult.

Behind the pink curtain, Au Bonheur du Jour, an art gallery of erotic archives.

A church of bones, decorated with 40,000 human skeletons.

These "anatomical machines" are only one of the many strange items in this Italian crypt.

Stroll through retro Paris while shopping for old postcards and discarded doll heads.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

Weird wax anatomical models reside here, as do other anatomical specimens.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

Paris' fabled purveyor of exotic taxidermy and natural history curios.

Inside a former cabaret, seven floors of erotic art.