The area of Chelyabinsk contained the ancient settlement of Arkaim, which belonged to the Sintashta culture. In 1736, a fortress by the name of Chelyaba was founded on the site of a Bashkir village. Chelyabinsk was granted town status by 1787. Chelyabinsk began to grow rapidly by the early 20th century as a result of the construction of railway links to European Russia and Siberia, including the Trans-Siberian Railway. Its population reached 70,000 by 1917. Under the Soviet Union, Chelyabinsk became a major industrial centre during the 1930s. The Chelyabinsk Tractor Plant was built in 1933. During World War II, the city was a major contributor to the manufacture of tanks and ammunition.