Castel Sant' Angelo - Rome, Italy
Castel Sant' Angelo was built to be used as Emperor Hadrian's family mausoleum between 135 AD and 139 AD. It has since been used as a fortress, Papal residence and a military prison. The building is cylindrical in shape and a wide stone ramp winds its way from the ground floor to the upper terraces. The building consists of a number of passageways and Papal apartments as well as old dungeons.
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