Malta (Republic of Malta; Repubblika ta' Malta) is a Parliamentary republic, situated in the middle of the Mediterranean, with the largest inhabited island, Malta, lying 93 km south of Sicily and 290 km from North Africa. Gozo and Comino are the only other inhabited islands. Malta became a member of the European Union, on May 1, 2004. The Maltese archipelago is formed from limestone sedimentary rocks formations, with high rocky cliffs, interrupted, from deep inlets. The interior is rather flat, the maximum elevation is the Nadur Tower, 239 meters. The land is dry and rich of karst phenomena, it lack practically of water courses.