There is evidence of continuous human habitation in present-day Thailand from 20,000 years ago to the present day. The earliest evidence of rice growing is dated at 2,000 BCE. Bronze appeared circa 1,250–1,000 BCE. The site of Ban Chiang in northeast Thailand currently ranks as the earliest known centre of copper and bronze production in Southeast Asia. Iron appeared around 500 BCE. The Kingdom of Funan was the first and most powerful Southeast Asian kingdom at the time (2nd century BCE). The Mon people established the principalities of Dvaravati and Kingdom of Hariphunchai in the 6th century. The Khmer people established the Khmer empire, centred in Angkor, in the 9th century. Tambralinga, a Malay state controlling trade through the Malacca Strait, rose in the 10th century. The Thai people are of the Tai ethnic group, characterised by common linguistic roots.