Eritrea (IPA: /ˌɛrɨˈtreɪə/, /ˌɛrɨˈtriːə/) (Ge'ez: ʾErtrā, Arabic: إرتريا Iritriya), officially the State of Eritrea, is a country in Northeast Africa. It is bordered by Sudan in the west, Ethiopia in the south, and Djibouti in the southeast. The east and northeast of the country have an extensive coastline on the Red Sea, directly across from Saudi Arabia and Yemen. The Dahlak Archipelago and several of the Hanish Islands are part of Eritrea. Eritrea is a multilingual and multicultural country with two dominant religions (Coptic Orthodox Christianity and Islam) and nine ethnic groups. The country's dominant language is Tigrinya, natively spoken by about 50% of the population. Along with Tigrinya, Arabic and English are used as working languages. English is also used in all of the government's international communication and is the language of instruction in all education beyond the fifth grade. Eritrea is located in East Africa, more specifically in the Horn of Africa, and is bordered on the northeast and east by the Red Sea. The country is virtually bisected by one of the world's longest mountain ranges, the Great Rift Valley, with fertile lands to the west, descending to desert in the east. Eritrea, at the southern end of the Red Sea is the home of the fork, in the rift. The Dahlak Archipelago and its fishing grounds are situated off the sandy and arid coastline. The land to the south, in the highlands, is slightly drier and cooler. The Afar Triangle or Danakil Depression of Eritrea is the probable location of a triple junction where three tectonic plates are pulling away from one another: the Arabian Plate, and the two parts of the African Plate (the Nubian and the Somali plate) splitting along the East African Rift Zone (USGS). The highest point of the country, Emba Soira, is located in the center of Eritrea, at 9,902 ft (3,018 metres ) above sea level. The main cities of the country are the capital city of Asmara and the port town of Asseb in the southeast, as well as the towns of Massawa to the east, and Keren to the north.