Information on Yemen.

Yemen is in the Middle East, in the south of Arabia, bordering the Arabian Sea, Gulf of Aden, and Red Sea, west of Oman and south of Saudi Arabia. It is considered to be one of the fifteen states that comprise the Cradle of Humanity.

The Red Sea islands: Hanish Islands, Kamaran and Perim as well as Socotra in the Arabian Sea belong to the Yemen

Until recently its northern border was undefined because the Arabian Desert prevented any human habitation there.

The country can be divided geographically into four main regions: the coastal plains in the west, the western highlands, the eastern highlands, and the Rub al Khali in the east.

The Tihamah ("hot lands") form a very arid and flat coastal plain. Despite the aridity, the presence of many lagoons makes this region very marshy and a suitable breeding ground for malarial mosquitoes. There are also extensive crescent-shaped sand dunes. The evaporation in the Tihama is so great that streams from the highlands never reach the sea, but they do contribute to extensive groundwater reserves - which today are heavily exploited for agricultural use.

The Tihamah ends abruptly at the escarpment of the western highlands. This area, now heavily terraced to meet the demand for food, receives the highest rainfall in Arabia, rapidly increasing from 100mm (4 inches) per year to about 760mm (30 inches) in Ta'izz and over 1000mm (40 inches) in Ibb. Agriculture here is very diverse, with such crops as sorghum dominating, but cotton and many fruit trees are also grown, with mangoes being the most valuable. Temperatures are hot in the day but fall dramatically at night. There are perennial streams in the highlands but these never reach the sea because of high evaporation in the Tihama.

Sanaá, the capital of Yemen.The central highlands are an extensive high plateau over 2,000 metres (6,560 feet) in elevation. This area is drier than the western highlands because of rain-shadow influences, but still receives sufficient rain in wet years for extensive cropping. Diurnal temperature ranges are among the highest in the world: ranges from 30°C (86°F) in the day to 0°C (32°F) at night are normal. Water storage allows for irrigation and the growing of wheat and barley. Sana'a is located in this region. The highest point in Yemen is Jabal an Nabi Shu'aya, at 3,760 meters (12,336 ft).

The Rub al Khali in the East is much lower, generally below 1,000 metres, and receives almost no rain. It is populated only by Bedouin herders of camels.