The Tihamah is a nearly 419-kilometre (260 mi) long, semidesert coastal plain that runs along the Red Sea and is part of the Arabian Peninsula coastal fog desert ecoregion.
As of February 2004, Yemen is divided into twenty governorates (muhafazat) and one municipality called "Amanat Al-Asemah" (the latter containing the capital, Sana'a)
With Jebel Nugum towering over it, Sana'a sits on the narrowest point of a major mountain plateau, (2.286 metres) above sea level. The region's volcanic origin and regular rainfall make it fertile and it enjoys a temperate climate throughout the year with the occasional sharp frost in the small hours of winter nights. One legend tells of its founding by Shem the son of Noah.