A fairy tale castle in modern Rome.

Architectural monsters are devouring this palace's every door and window.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

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

The first tunnel to be dug beneath a river, repurposed as an art and museum space.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

Charles Babbage's proto-computer, painstakingly brought to life.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

A Victorian natural history and ethnographic museum with wonderful turn-of-the-century, science-book-esque evolution displays.

A mysterious artist-run cabinet of curiosities and library.

Remnants of a Victorian garden feature sitting in public woodland.

The curios of pharmacist and collector Henry Wellcome.

The only university zoological museum in London houses extinct animals, bizarre natural history specimens, and a Micrarium of microscopic creatures.

Eighty million natural history specimens call this gargantuan museum home.

A tongue-in-cheek arcade where the games are based on everyday life.

This collection of illusory paraphernalia has been culled from the history of London's premier magician's club.

The world's first underground farm is in a World War II bomb shelter beneath the streets of London.

This shop and gallery is a modern-day cabinet of curiosities, unassumingly positioned along an urban thoroughfare.