La Villa Zanelli in Savona, Italy. Built in 1907 and then sold to the municipality of Milan, which transformed it into a camp and international colony, then during WWII as a field hospital.
Source: Reddit
Just outside of Savona, Italy, on a beach is an oddly beautiful villa called La Villa Zanelli that was built in 1907. A sea captain named Nicolo Zanelli had it built for him and his family, who lived in it until 1933. At that time, it was sold to the municipality of Milan and later used during World War II as a field hospital. Then in 1967, it became a heart center up until 1998, when a ceiling collapsed. After that happened, it was left abandoned and exposed to vandals. Efforts are now being taken to try to restore it through awareness on a FB page and setting up a fund collecting account.