Abdulaziz, faced opposition from most in the royal family and was eventually deposed. Faisal replaced Saud in 1964. Until his murder by a nephew in 1975, Faisal presided over a period of growth and modernization fuelled by oil wealth. Saudi Arabia's role in the 1973 oil crisis, and the subsequent rise in the price of oil, dramatically increased the country's political significance and wealth. Khalid, Faisal's successor, reigned during the first major signs of dissent: Islamist extremists temporarily seized control of the Grand Mosque in Mecca in 1979. Fahd became king in 1982. During his reign, Saudi Arabia became the largest oil producer in the world. However, internal tensions increased when the country allied itself with the United States, and others, in the 1991 Gulf War. In the early 2000s, the Islamist opposition to the regime carried out a series of terrorist attacks. Abdullah succeeded Fahd in 2005. He instituted a number of mild reforms to modernize many of the country's institutions and, to some extent, increased political participation. Salman became king in 2015, at the age of 79. He oversaw the reorginazation of the Saudi government and bestowed most of the king's political power into the crown prince, whom he replaced twice. Salman's son and current crown prince, Mohammed bin Salman, effectively controls the government. Mohammed has been responsible for the controversial Saudi intervention in the Yemeni Civil War. He has overseen a number of legal and social reforms in the country, while also seeking to diversify the economy with Saudi Vision 2030. Pre-Islamic Arabia There is evidence that human habitation in the Arabian Peninsula dates back to about 63,000 years ago. Nevertheless, stone tools from the Middle Paleolithic age, along with fossils of other animals discovered at Ti's al Ghadah, in northwestern Saudi Arabia, might imply that hominids migrated through a "Green Arabia" between 300,000 and 500,000 years ago. Archaeology has revealed some early settled civilizations: the Dilmun civilization on the east of the Arabian Peninsula, the Thamūd north of the Hejaz, the Kingdom of Kinda in the centre, and the Al-Magar civilization in the southwest of the Arabian Peninsula. The earliest known events in Arabian history are migrations from the peninsula into neighbouring areas. There is also evidence from Timna (Israel) and Tell el-Kheleifeh (Jordan) that the local Qurayya/Midianite pottery originated within the Hejaz region of northwestern Saudi Arabia, which suggests that the biblical Midianites originally came