Ramsar is a city and the capital of Ramsar county, Mazanfaran Province, Iran. At the 2006 census, its population was 31,659. Ramsar lies on the coast of the Caspian Sea. IOt was also known as Sakhtsar in the past. Natives of Ramsar speak the Gilaki Language which is a member of Northwest Iranian languages. The town is known for having the highest levels of natural background radiation on earth.