Experts believe the wall in Golestan Province was constructed centuries ago, the Fars News Agency reported Monday. It was used to defend against by nomadic tribes from Central Asia, called the Ephthalites, who invaded the region in the 5th and 6th centuries.

The team of British and Iranian archaeologists also found a 31-mile-long section of a canal near the wall they believe was used to move water from the Gorganrud River to people living nearby. Iranian team leader Hamid Omrani said canal section was still in use until the 1979 Islamic Revolution when French engineers built the Voshmgir Dam, the news agency said.

China's Great Wall was about 4,000 miles long and was built over several hundred years beginning in the 5th century.