The uninhabited Mamula Island sits on the border between Montenegro and Croatia, and with a diameter of just 200 metres, it's barely visible on a map.
The island is dominated by a 19th-century fort, which the Italian Army used as a concentration camp during World War II under the rule of dictator Benito Mussolini.
CNN reported that more than 2,300 people were imprisoned there, with 130 killed or starved to death.
The existing fort was originally built in 1853 by Austrian Admiral, Lazar Mamula, in order to protect Boka Bay from entering enemy ships. The island however never served its purpose, as there was never a military attack.
AFP, "To build a luxury hotel dedicated to entertainment at this place where so many people perished and suffered is a blatant example of lack of seriousness towards history."