Benxi is a prefecture-level city located in the east of Liaoning Province in Northeast China, south-southeast of Shenyang. Its population is 1,709,538 at the 2010 census whom 959,610 in the built up area It was founded as a metallurgical center in 1915. The second largest industry in Benxi is coal mining. Benxi has pollution problems due to steel production and coal mining. During the Warring State Period (476 BC-221 BC), present day downtown Benxi and Benxi County fell under the rule of the Yan Kingdom. The Gaoyi, an ancient tribe in northeastern Asia, occupied the remaining areas of Benxi. In 37BC, the Korean Koguryo Kingdom was established around the Huanran Manchu Autonomous County. The Koguryo Kingdom drew to a close in the Tang Dynasty (608-907).