The Danube Delta is the second largest river delta in Europe, after the Volga Delta, and is the best preserved on the continent. The greater part of the Danube Delta lies in Romania (Tulcea County), while its northern part, on the left bank of the Chilia arm, is situated in Ukraine (Odessa Oblast). Its approximate surface area is 4,152 km2 (1,603 sq mi), of which 3,446 km2 (1,331 sq mi) is in Romania. With the lagoons of Razim–Sinoe (1,015 km2 (392 sq mi) with 865 km2 (334 sq mi) water surface), located south of the main delta, the total area of the Danube Delta is 5,165 km2 (1,994 sq mi). The Razim–Sinoe lagoon complex is geologically and ecologically related to the delta proper and the combined territory is listed as a World Heritage Site.