Description:Take a tour of Castel del Monte in Italy – part of the World’s Greatest Attractions series by GeoBeats.
South Italy's Castel del Monte is a stunning monument of medieval architecture.
It was completed in 1240 under the Holy Roman Emperor Frederick the second.
First used as a hunting lodge, Castel del Monte later became a prison.
It also found use as a sanctuary during the time of the plague.
The Italian government bought the fortress in 1876.(0:57)