Sistan

Also spelled  Seistan,   extensive border region, eastern Iran and southwestern Afghanistan. Forty percent of its area is in Iran, as well as the majority of its sparse population. The region comprises a large depression some 1,500–1,700 feet (450–520 m) in elevation. Numerous rivers fill a series of lagoons (hamun) and in high flood form a shallow lake that spills into another depression to the south. Three large deltas