is a mountainous country in South Asia surrounded by several more powerful countries including Iran, India, China, Mongolia, Pakistan, and other "-stan" countries near Russia. The Afghanistan area has been invaded many times in recorded history. Invaders of Afghanistan include Alexander the Great, Genghis Khan, Timur, the Mughal Empire, Russian Tsars, the British Empire, the Soviet Union, and currently a coalition force of NATO troops, the majority of which are from the United States, following the US-led invasion which began on October 7, 2001, Operation Enduring Freedom. Alexander the Great, fighting the Persian king Darius (Pompeii mosaic, from a 4th century BC original Greek painting, now lost).  Purpose From a geopolitical sense, controlling Afghanistan is vital in controlling Southern Asia. Afghanistan played an important part in the Great Game power struggles. Current struggles over Afghanistan can be viewed as an extension of the struggle over control over Southern Asia and its natural resources, as well as its strategic location in the middle of Eurasia. Historically, the conquest of Afghanistan has also played an important role in the invasion of India from the west through the Khyber Pass.  History  Early invasions The first historically documented invasion of the Afghanistan region was by Alexander the Great in 330 BC as part of his string of conquests. Among the cities conquered were Herat and Kandahar. In the seventh to ninth centuries the area was again invaded from the west in the Islamic conquest of Afghanistan, resulting in the conversion of most of its inhabitants to Islam. This was one of many Muslim conquests following the establishment of a unified state in the Arabian Peninsula by the prophet Muhammad. At its height, Muslim control extended throughout the Middle East, North Africa, and most of the Iberian Peninsula (modern day Spain and Portugal). In the Mongol invasion of Khwarezmia (1219—1221), Genghis Khan invaded the region from the northeast in one of his many conquests to create the huge Mongol Empire. Unlike earlier campaigns in Mongolia and China, Genghis Khan's armies completely destroyed Khwarazmia and brutally killed vast numbers of its civilians. From 1383 to 1385, the Afghanistan area was conquered from the north by Timur, leader of neighboring Transoxiana (roughly modern-day Uzbekistan, Tajikistan, and adjacent areas), and became a part of the Timurid Empire. Timur was from a Turko-Mongol tribe and although a Muslim, saw himself more as an heir of Genghis Khan. Timur's armies caused great devastation and are estimated to have caused the deaths of 17 million people. After the end of the Timurid Empire in 1506, the Mughal Empire was later established in Afghanistan and India by Babur in 1526, who was a descendant of Timur through his father and possibly a descendant of Genghis Khan through his mother. By the 17th century, the Mughal Empire ruled most of India, but later declined during the 18th century.  British invasions During the nineteenth century, Afghanistan was invaded twice from British India, during the First Anglo-Afghan War of 1838–1842 and again in the Second Anglo-Afghan War of 1878–1880, both times with the intention of limiting Russian influence in the country and quelling local tribal leaders. For the entire period, tribal cross-border warfare was constant, and parts of the Pashtun homeland were annexed to British India and referred to as the North-West Frontier Province. The Mughal Empire was dissolved by the British following the Indian Rebellion of 1857 and its last leader, Bahadur Shah II, was exiled to Burma.  Soviet intervention Soviet troops withdrawing from Afghanistan in 1988. Main article: Soviet war in Afghanistan The Soviet Union, along with other countries, was a direct supporter of the new Afghan government after the Saur Revolution in 1978. However, Soviet-style reforms introduced by the government such as changes in marriage customs and land reform were not received well by a population deeply immersed in tradition and Islam. By 1979, fighting between the Afghan government and various other factions within the country, some of which were supported by the United States and other countries, led to a virtual civil war. The Afghan government requested increasing Soviet military support and eventually direct military involvement. Soviet President Leonid Brezhnev sent the 40th Army into Afghanistan on December 24, 1979. This event led to the boycott of the 1980 Summer Olympics in Moscow by the United States and other countries, and kick-started U.S. funding for Islamic Mujahideen groups who opposed the Afghan government and the Soviet military presence. The local Mujahideen, along with fighters from several different Arab nations (Pathan tribes from Pakistan also participated in the war; they were supported by ISI), eventually succeeded in forcing the Soviet Union out. This was a factor in the dissolution of Soviet communism, because it led to protests (similar to American Vietnam War protests) in the Soviet Union. Eventually, in-fighting within the Mujahideen led to the rise of warlords in Afghanistan, and from them emerged the Taliban.  Invasion by the United States and allies U.S. Army soldiers prepare a Humvee to be sling-loaded by a CH-47 Chinook helicopter in Bagram on July 24, 2004. Main articles: Operation Enduring Freedom and War in Afghanistan (2001–present) On October 7, 2001 the United States, supported by some NATO countries including the United Kingdom and Australia, as well as other allies, began an invasion of Afghanistan under Operation Enduring Freedom. The invasion was launched to capture Osama bin Laden, who was accused of the September 11, 2001 attacks. The US military forces did not capture him, though they toppled the Taliban government and disrupted bin laden's Al-Qaeda network. The Taliban government had given shelter to Bin Laden. On May 2, 2011, bin Laden was shot and killed by United States Armed Forces. The Taliban leadership survives in hiding in Afghanistan, largely in the southeast, and continues to launch terrorist attacks against forces of the United States, its allies, and the current government of President Hamid Karzai. In 2006, the US forces turned over security of the country to NATO-deployed forces in the region, integrating 12,000 of their 20,000 soldiers with NATO's 20,000. The remainder of the US forces continued to search for Al-Qaeda militants. The Canadian military assumed leadership and almost immediately began an offensive against areas where the Taliban guerrillas had encroached. At the cost of a few dozen of their own soldiers, the British, American, and Canadian Forces managed to kill over 1,000 alleged Taliban insurgents and sent thousands more into retreat. Many of the surviving insurgents, however, began to regroup and further clashes are expected by both NATO and Afghan National Army commanders.