The only visible reminders of an elaborate engineering project that kept the tower from reaching the tipping point.

An unusual "skull with ears" sits in the crypt of this small church tucked away at the end of a narrow alley.

This sword isn't waiting for a king to pull it out. It was placed there by a saint.

Burbling away in refrigerators are 105 sourdough starters from around the world.

These ruins reveal the remarkably intact layout of a Roman marketplace.

This abandoned coliseum was intended to be a grand Nazi rallying ground before it was halted at the end of the war.

On rare days, this abandoned castle's gatekeepers open its doors, revealing the eye-popping splendor hidden inside.

David Sedaris called it "The greatest shop in the world."

A factory director designed what was the world's longest suspension footbridge in 1923 so his employees could get to work safely.

Medical history with an amazing, if frighting, collection of wax diseases on display.

Caligula's colossal pleasure ships, discovered by Mussolini only to be lost in flames.

An underground paleo-Christian burial site composed of the remains of several cemeteries and Basilicas.

Hidden in an Italian forest is a completely homemade amusement park that has taken a lifetime to create.

A 16th-century horror show built in a lovely Italian garden.

An amazing collection of wax anatomical models and terratological models.

Anatomical cabinet holds unexpected treasures.

A morbid secret lies hidden within the beautiful walls of the Boston Athenaeum.

The remains of the great moral philosopher reside in a university in London.

A cluttered and astounding collection of antiquities and curiosities.