18 Unsolved Mysteries That Have Been Thoroughly Solved

150,000 Year Old Plumbing

The Baigong pipes, which are also known as ????? (Bai Gongshan Iron Pipes) and Delingha pipes, are a series of pipe-like features identified as fossil trees or tree roots, found on and near White Mountain (Chinese: ???; pinyin: Báigongshan 'Mount Baigong'), about 40-kilometer (25 mi) southwest of the city of Delingha, in the Haixi Mongol and Tibetan Autonomous Prefecture, Qinghai Province, China.