Castel Sant'Angelo

The Mausoleum of Hadrian, usually known as the Castel Sant'Angelo (English: Castle of the Holy Angel), is a towering cylindrical building in Parco Adriano, Rome, Italy. It was initially commissioned by the Roman Emperor Hadrian as a mausoleum for himself and his family. The building was later used by the popes as a fortress and castle, and is now a museum.

• http://en.wikipedia.org/wiki/Castel Sant'Angelo
• Hillman 1000 Wonders