On top of a small hill overlooking the comune of Andria, in the Italian region Apulia, stands one of the strangest looking castle. This 13th century citadel is octagonal in shape, with each of the eight corners sporting an octagonal tower. Its geometric design was very unique at that time.

The castle was built in 1240 by the Holy Roman Emperor Frederick II, but nobody knows why. It was not built to defend anything, as it has neither a moat nor a drawbridge, although archaeological work suggest there might have been originally a curtain wall. Some believe that Castel del Monte was nothing more than a hunting lodge.

Photo credit: Batmagazine