contaminated in 1957 from a storage tank explosion, only one of several serious accidents that further polluted the region. The 1957 accident expelled 20 million curies of radioactive material, 90% of which settled into the land immediately around the facility. Although some reactors of Mayak were shut down in 1987 and 1990, the facility keeps producing plutonium. Cultural significance The Urals have been viewed by Russians as a "treasure box" of mineral resources, which were the basis for its extensive industrial development. In addition to iron and copper, the Urals were a source of gold, malachite, alexandrite, and other gems such as those used by the court jeweller Fabergé. As Russians in other regions gather mushrooms or berries, Uralians gather mineral specimens and gems. Dmitry Mamin-Sibiryak (1852–1912) Pavel Bazhov (1879–1950), as well as Aleksey Ivanov and Olga Slavnikova, post-Soviet writers, have written of the region. The region served as a military stronghold during Peter the Great's Great Northern War with Sweden, during Stalin's rule when the Magnitogorsk Metallurgical Complex was built and Russian industry relocated to the Urals during the Nazi advance at the beginning of World War II, and as the center of the Soviet nuclear industry during the Cold War. Extreme levels of air, water, and radiological contamination and pollution by industrial wastes resulted. Population exodus followed, and economic depression at the time of the collapse of the Soviet Union, but in post-Soviet times additional mineral exploration, particularly in the northern Urals, has been productive and the region has attracted industrial investment. Gallery See also Yugyd Va National Park Dyatlov Pass incident East Ural Radioactive Trace Idel-Ural State Pangea Research Range Ural Mountains in Nazi planning References External links Peakbagger.com page on the Ural Mountains Ural Expeditions & Tours page on the five parts of the Ural Mountains Mountain ranges of Russia Mountain ranges of Kazakhstan Landforms of Siberia Landforms of Arkhangelsk Oblast Landforms of Bashkortostan Landforms of Chelyabinsk Oblast Landforms of Khanty-Mansi Autonomous Okrug Landforms of the Komi Republic Landforms of Nenets Autonomous Okrug Landforms of Sverdlovsk Oblast Landforms of Tyumen Oblast Aktobe Region Novaya Zemlya Geology of Russia Mountain ranges of Asia Mountain ranges of Europe Physiographic divisions History of Ural Turkic toponyms