There are several fertile oases in these regions that are living examples of ancient Iranians determination to survive and bestow life to the arid areas.

There are numerous rivers in Iran , but nearly all of them are relatively short, shallow streams unsuitable for navigation. The country's only navigable river, the Karun , flows through the city of Ahvaz in the southwest and empties to the Persian Gulf . Most rivers originate from the mountains and drain into the interior basins. 

Although around 1/3 of Iran 's total territory is arable, only %10.4 is under cultivation. An additional %6 of the total land is used for pasture. Forested areas have declined slightly in recent decades and account for %4.5 of the total territory.

The country's capital and largest city, Tehran , serves as the main administrative, financial, industrial, commercial, educational and publishing center. Iran 's other major cities include Shiraz , Esfehan, Tabriz , Mashad and Ahvaz .

Shiraz is a manufacturing center in the south near the ruins of the most glorious ancient Persian monument called Persepolis .

Esfehan is a manufacturing center with several masterpieces of Islamic architecture from the 17th and 18th centuries.

Tabriz is the principal industrial and commercial center of the northwest.

Mashad is a manufacturing and commercial center in the northeast and the site of the country's most important religious shrine where the body of the eighth Imam of Shiites has been buried. And Ahvaz is the major commercial and manufacturing center in the southwest of Iran .