Egypt is located in the northeast corner of Africa and is often considered part of the Arab world. The earliest kingdoms were located around the Nile River and Delta. In 3200 BCE, the Upper and Lower kingdoms united and were an independent country until they were conquered in 341 BCE by the Persian empire. During the next several centuries the country fell under the dominion of several empires, including the Greek, Roman, Byzantine, Arab, Ottoman, and British, with brief periods of self government. It finally gained independence in 1952. Egypt has struggled somewhat with modernization and tensions in the area during the 20th century. Its citizens took part in the Arab Spring beginning in 2010, ousting then-president Hosni Mubarak, and electing Mohammed Morsi, candidate from the Muslim Brotherhood organization. Morsi was ousted in 2013, following mass protests; the Egyptian army took control of the country as an interim measure, until presidential elections reoccurred in May 2014 with Abdul Fattah al-Sisi, a former army chief, winning the election.