Country at the south end of the Arabian peninsula, bordering Saudi Arabia (with whom much of the border is undefined) and Oman (as well as the Red Sea and the Gulf of Aden. Used to be the separate countries of North Yemen (Yemen Arab Republic) and South Yemen (People's Democratic Republic of Yemen); the two merged in 1990. The CIA World Factbook describes it as "one of the poorest countries in the Arab world," but since it does have oil, it's not poor compared to a lot of countries.