Iran Officially Islamic Republic of Iran, republic in southwestern Asia. Iran is bordered on the north by Armenia, Azerbaijan, Turkmenistan, and the Caspian Sea; on the east by Afghanistan and Pakistan; on the south by the Gulf of Oman, the Strait of Hormuz, and the Persian Gulf; and on the west by Iraq and Turkey. The area of Iran is about 1,648,195 sq km. Until the 1930s Iran was known abroad as Persia. The capital and largest city is Tehran (Teheran). Iran is dominated by a central plateau, which is about 1200 m (about 4000 ft) high and is almost ringed by mountain chains. In the north, paralleling the southern shore of the Caspian Sea, are the Alburz Mountains. The highest peak in Iran, Mount Damavand (5604 m/18,386 ft), is part of this mountain system. The Caspian Sea, at 28 m (92 ft) below sea level, is the lowest point in Iran. Along the western border the complex Zagros Mountains extend southeast to the region bordering the Persian Gulf. Mountains of lower elevation lie to the east of the central plateau. Except for the relatively fertile plateaus of the northern Iranian provinces of Azerbaijan, mountain soils are thin, heavily eroded, and infertile. The narrow Caspian coastal plain, in contrast, is covered with rich brown forest soil. The only other generally flat area is the plain of Khuzestan (Khuzistan) in the west.Two great deserts extend over much of central Iran. The Dasht-e Lut is covered largely with sand and rocks, and the Dasht-e Kavir is covered mainly with salt. Both deserts are inhospitable and virtually uninhabited. In the winter and spring small streams flow into the Dasht-e Kavir, creating little lakes and swamps. In other times of the year both deserts are extremely arid. Most of Iran’s rivers flow only during part of the year, when precipitation is heaviest. The country’s principal permanent rivers flow off the mountains on the slopes facing the Caspian Sea, the Persian Gulf, or the Gulf of Oman. The Karun River, flowing from the Zagros Mountains to the Shatt al Arab at Khorramshahr, is the country’s main navigable river. Besides the Caspian Sea, Iran has few large lakes. Most shrink in size during the hot, dry summer and have a high salt content because they have no outlet to carry away the salt left when the water evaporates. The largest water body entirely within Iran is Lake Orumieh, in the northwest. Iran is divided climatically into three main regions: the extremely hot coast along the Persian Gulf and the Gulf of Oman; the temperate but arid central highland; and the tableland of the intensely cold Alburz Mountains. The average temperature range in Tehran on the interior plateau is -3° to 7° C (27° to 45° F) in January and 22° to 37° C (72° to 99° F) in July. The average range in Abadan on the Persian Gulf is 7° to 17° C (44° to 63° F) in January and 28° to 44° C (82° to 112° F) in July. Average annual precipitation in Tehran is about 250 mm (about 10 in), and in Abadan is less than 200 mm (less than 8 in). On the semihumid plateaus of Iran, grass cover is used for grazing livestock. The Zagros Mountains have a semi humid forest cover dominated by oak, elm, pistachio, and walnut trees. On the seaward slopes of the Alburz Mountains and on the Caspian plain, vegetation is abundant. In these areas broadleaf deciduous trees such as ash, elm, oak, and beech flourish, along with some broadleaf evergreens, ferns, and shrubs. On the arid plateaus, scrub and cactus growth dominate. Iran has a wide variety of native wildlife including the rabbit, fox, wolf, hyena, jackal, leopard, deer, porcupine, ibex, bear, badger, weasel, and tiger. Pheasants and partridges are found inland; pelicans and flamingos breed along the Persian Gulf. Sturgeon, whitefish, and herring inhabit the Caspian Sea.