Russia's interest in Afghanistan is not new. Moscow's imperial expansion into Central Asia in the 19th century coincided with British expansion in India, during a time of competition known as the Great Game. As tension between Britain and Russia mounted, Afghanistan became a buffer zone between the two in Central Asia. Eventually, once the Russian Empire transitioned into the Soviet Union, the once open borders between Afghanistan and Central Asia were closed, differentiating its culture and governing structure considerably from other Central Asian countries. But despite the closure of the border, Afghanistan's links with other Central Asian nations were not completely severed. Eventually, in 1979, the Soviets invaded Afghanistan, becoming embroiled in a decadelong conflict to prop up a Russia-friendly communist government. The Afghanistan war was enormously costly for the Soviet Union, which withdrew in a stalemate in 1989, just two years before its collapse.