Greece
Greece's first and Europe's largest marine protected area, centred on Alonnisos and six smaller Sporades islands, protecting the Mediterranean monk seal and offering wall, reef and cave diving plus the ancient Peristera...
Established by presidential decree on 16 May 1992, the park covers about 2,260 km2, the largest marine protected area in Europe. It encompasses Alonnisos plus Peristera, Kyra Panagia, Gioura, Psathoura, Piperi and Skantzoura, created primarily to protect the Mediterranean monk seal. Diving is permitted only in designated zones with 21 accessible dive sites (walls, reefs, caverns, gorgonian gardens). The Peristera shipwreck, dating to the 5th century BC, is considered the oldest accessible shipwreck in the world. Source: Wikipedia (Alonnisos Marine Park), bestdivingingreece.com.