Erotic art covers the walls of the largest ancient pleasure palace.

This abandoned Brutalist treehouse is a hidden architectural relic.

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

The one-stop shop for all of your superhero (or evil arch-nemesis) needs.

One of the most important yet well-hidden museums dedicated to the history of medicine.

The mystic whose incorrupt corpse still attracts the faithful.

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

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