Castel del Monte
Crowning an isolated hill 1,778 feet above sea level in the heart of the Alta Murgia National Park, this enigmatic octagonal fortress, built by Frederick II in the first half of the 13th century, has puzzled historians and researchers for centuries. Rooms are arranged in a seemingly illogical sequence through eight towers around a central courtyard. Recent interpretations suggest it was an elaborate cultural center conceived by Frederick to study various scientific disciplines of the Western and the Arabic worlds. Umberto Eco used it as his inspiration for riddles in The Name of the Rose. To avoid disappointment: it's an impressive if largely empty building, and can be tricky to get to and pricey to visit when adding parking, guided tours, and so on.
