Two stunning 17th-century libraries and a cabinet of curiosities.

Macabre astrological automaton clock dating to the late 1400s.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

Turntable anonymously received orphans, alms, and groceries.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

A series of caves under Castle Hill that once held the prisoner Vlad Tepes, better known as Count Dracula.

The mummified right fist of a 1,000-year-old saint-king sits inside an ornate golden reliquary.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

An unusual round church in London with a Templar past.

The largest of London's subterranean rivers and once a mad, bad center of London life.

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

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

The American Revolution was galvanized into serious action due to the tragic clash with British soldiers that occurred at this location.

This massive tea kettle was once a promotional stunt for the Oriental Teashop.

This headstone marks the grave of an 11-year-old boy killed during clashes in the streets over the boycotting of British goods.

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

Two thousand artifacts from around the world collected by one woman who loved to travel.

Unlike other abandoned asylums this empty institution welcomes visitors, just don't go in the buildings.

The inspiration for H.P. Lovecraft's horror stories and Batman's Arkham Asylum is now a condominium complex.

The former site of an all-but-forgotten colonial landmark is now remembered by an often overlooked bas relief.

Dim sum, served in a grand old theater.

American revolutionaries and British soldiers alike are buried here in the fourth-ever cemetery in Boston.

Statue commemorating the use of ether in anesthesia.