Once a Roman emperor's tomb, later a fortress, a prison and even a papal hideaway, Castel Sant'Angelo is packed with mysteries and stories. Follow the clues and uncover the secrets hidden inside one of Rome's most extraordinary buildings.

Along the way, you'll discover:

• Why a mysterious Roman bust has earned the nickname "Lord Voldemort"

• The secret passage used by popes to escape danger

• How a Roman emperor's tomb became a mighty fortress

• The legends and mysteries hidden within the castle walls

• Spectacular views across Rome from the top of the fortress

...and plenty more secrets hidden inside this remarkable building.