The largest lake in Romania, Razim-Sinoe is where the sweet water of Danube and the salt water of the Black Sea meet. Razim-Sioe is a network of interconnected lakes close to the Black Sea. It is about 730 km2 large, the largest lake in Romania. Razim itself occupies more than half of its surface. It has a maximum depth of 3m. There are two places where the lakes communicate with the Black Sea. It is also connected to Sfantu Gheorghe branch of the Danube. Popina island is located in the middle of the lake and it is a protected reservation. On the shore of Sinoe lake, there's a place called Histria, where the ruins of a thousands of years old Greek citadel are located.