Yemen is a desert country in the Middle East on the southern tip of the Arabian Peninsula, bordered in west by the Red Sea and the Bab-el-Mandeb Strait, in north by Saudi Arabia and in north east by Oman. Yemen has maritime borders with Djibouti, Eritrea, and Somalia. With an area of 527,970 sq km (including the islands of Perim and Socotra), 26 million people live in the country. Largest city and the national capital is Sana'a, situated in a mountain valley at an altitude of 2,200 m, the Old City of Sana'a is a UNESCO World Heritage Site. Yemen's primary seaport and economic center is Aden. Official language is Arabic.