Dasht-e Kavir (däsht-ēkävērˈ) [key], great salt desert, c.500 mi (800 km) long and c.200 mi (320 km) wide, SE of the Elburz Mts., N central Iran. It is a huge basin of interior drainage named after the kavirs (salt marshes) located there. The Kavir Buzurg (Great Kavir), c.200 mi (320 km) long and c.100 mi (160 km) wide, lies in the heart of the region; low sandy hills separate it from smaller kavirs. An almost rainless climate with strong surface evaporation has created a crust of salt over the marsh and mud lands. Chemical salts balance the evaporation by drawing moisture from the substrata and the atmosphere. Because its kavirs have properties similar to quicksand, travel in the Dasht-e Kavir is extremely dangerous. It is almost uninhabited and only partly explored; settlement is restricted to the hills and surrounding mountains. Extending S from the Dasht-e Kavir is the Dasht-e Lut, a sand and stone desert, c.300 mi (480 km) long and c.200 mi (320 km) wide; it consists of dried-out kavirs and contains a large salt marsh. The two deserts occupy most of the central Iranian plateau.