Lake Varna

Lake Varna is the largest by volume and deepest liman or lake along the Bulgarian Black Sea Coast, divided from the sea by a 2 km-wide strip of sand and having an area of 19 km², maximal depth 19 m, and a volume of 166 million m³.

The lake has an elongated shape, its south shores are high, steep and wooded, and the north slant. Lake Varna was formed in a river valley by the raising of sea level near the end of the Pleistocene. Its bottom is covered by a thick alluvium of slime and hydrogen sulphide mud in the deepest parts; there are large deposits of medicinal fango. A number of rivers pour into the lake, including Devnya and Provadiyska that empty near the western shores of Lake Beloslav, which is connected to Lake Varna.

Source: Wikipedia