Yemen is an Arab country located in Western Asia, occupying the southwestern to southern end of the Arabian Peninsula. It is bordered by Saudi Arabia to the north, the Red Sea to the west, the Gulf of Aden and Arabian Sea to the south, and Oman to the east. It has an area of 555000 Yemen is one of the oldest centers of civilization in the Near East. Its capital and largest city is Sana'a. Yemen's territory includes more than 200 islands, the largest of which is Socotra, about 354 km (220 mi) to the south of mainland Yemen. It is the only state in the Arabian Peninsula to have a purely republican form of government. Yemen was the first country in the Arabian peninsula to grant women the right to vote. Yemeni unification took place on 22 May 1990, when North Yemen was united with South Yemen, forming the Republic of Yemen.