The Caspian Sea is the largest enclosed inland body of water on Earth by area, variously classed as the world's largest lake or a full-fledged sea. It is in an endorheic basin (it has no outflows) located between Europe and Asia. It is bounded to the northeast by Kazakhstan, to the northwest by Russia, to the west by Azerbaijan, to the south by Iran, and to the southeast by Turkmenistan.
The Caspian coastline is one of the most popular destinations for Iran's domestic tourists. Sandy beaches give way to wide open steppes, thickly forested foothills and eventually the bare peaks of the Alborz mountain range. For many Iranians, especially those from Tehran, the lush vegetation and spectacular natural scenery, along with the tropical summers and mild winters, offer a striking contrast from city life and the dry interior.
As a result, the three provinces of Gilan, Mazandaran and Golestan which front the Caspian Sea (in fact, the world's largest lake) are studded with resort complexes, leisure facilities and holiday homes.