"Built: 1568 Originally built in the 16th century as a summer home for an Italian cardinal, this stunning building was eventually converted into a hotel more than three centuries later. It now serves as a classic hotel with 25 acres of gardens that are absolutely immaculate. A favorite feature is the hotel's pool, which sits on a platform in the lake and is a major place for Italians (and Hollywood heavyweights) to see and be seen with estates that were once—and still are—owned by the likes of the Heinz family, Versace, and, of course, George and Amal Clooney."