Abandoned concert venue legendary for its rock counterculture.

A Beaux-Arts triumph set to become Ford's innovation campus

Controversial tribute to the heavyweight champion boxer who grew up in Detroit.

The Beaux-Arts aquarium boasts a vast collection of saltwater and freshwater fish on an island in the Detroit River.

The bones of an old zoo crumbling in the shadow of a new one.

Berry Gordy Jr.'s old home was the original headquarters of Motown Record Corporation.

Jesus' footprints and the first catacombs in the world.

2300-year-old Roman road connecting the empire.

The Pope’s secret escape route.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

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

Museum dedicated to literary greats of the Romantic Period is also the home in which Keats met his untimely end.

A Nesting Doll of Churches.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

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

The underground sanctuary of a mysterious ancient cult.

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

Breathtaking and huge 430 year old maps of Italy.

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

Ever loyal to Roma, the small village of Albe in the Abruzzo region carried on until an earthquake did it in.