Russia conquered Uzbekistan in the late 19th century. Stiff resistance to the Red Army after World War I was eventually suppressed and a socialist republic set up in 1924. During the Soviet era, intensive production of "white gold" (cotton) and grain led to overuse of agrochemicals and the depletion of water supplies, which have left the land poisoned and the Aral Sea and certain rivers half dry. Independent since 1991, the country seeks to gradually lessen its dependence on agriculture while developing its mineral and petroleum reserves. Current concerns include insurgency by Islamic militants based in Tajikistan and Afghanistan, a nonconvertible currency, and the curtailment of human rights and democratization.