In the north and west there are two large ranges of high mountains. Also a few smaller ranges of mountains run in the south, not very far from the coasts of the rersian Gulf and the Sea of Oman. These mountains bar the central regions from the humid winds coming from the Caspian Sea in the north, the Mediterranean in the west, and the Persian Gulf and the Sea of Oman in the south. Thus the external slopes of these mountains are green and the internal faces dry.
Iran consists of a high interior plateau surrounded by a series of massive, heavily eroded mountain ranges. Most of the country is over 509m above sea level. The capital, Tehran, lies at the foot of Alborz mountains and extends from an altitude of 1,300m to that of 1,600m . However, the coastal regions which lie beyond the mountains in the north and the south are quite low. In the north there is a narrow littoral, over 600 kilometers long, running along the Caspian sea, about 100 kilometers across where it is widest, and as narrow as 15 kilometers in many parts. The land falls from about 3,000 meters above the sea, down to 30m below sea level. Along the southern coast the land falls from about 700m to about sea level where it meets the Persian Gulf and the Sea of Oman.
The Zagros range of mountains runs from the northwest downwards in a south-easterly direction, then it turns east-wards and extends to Baluchestan but the west-east section is not called Zagros: different names are given to different parts of it. As Zagros mountains move from the northwest, south-wards slightly to the east, they broaden into almost parallel alternating ridges which separate central Iran from the plains of Mesopotamia.
The Alborz range, as forbidding as Zagros mountains, runs in the northern parts of the country close and parallel to the southern coast of the Caspian Sea. The highest summit is a volcanic peak more than 5,600m high, the snow-clad Mount Damavand.
At the eastern side, nlajestic mountains turn into low hills and sand dunes.
In the interior ylateau, most of which is desert-land or simply dry and barren, two other small ranges of mountains cut their way through. Parts of the central deserts are covered by sand and rocks. Small eases can be found here and there where some water can be had, and these usually mark the caravansaries, (or as the correct original Iranian word is caravansarays); stations on caravan routes for night rest and for trade. The plateau contains within It a salt waste, over 300 km long and about 10m wide: the "kavir." The central plateau, a high depression within these mountains, was at the one time the bed of a sea, which dried up tens uf thousands of years ago.