The (Landmarks August 15), September 16, 1997, Lanssila (Lanzhou - Xining - Lhasa) optical cable telecommunication laying across the board. In 1997, September 16, Lanzhou, Chengdu Military Region, more than 20,000 officers and men for more than two months of fighting, State Key Communication Engineering the --- Lanssila communication fiber optic cable lines across the board laying more than originally planned 25 days in advance, and highly praised by the State Ministry of Posts and Telecommunications, General Staff Communication Department. Lanzhou - Xining - Lhasa cable project a total length of 2,739 kilometers, passing through Gansu, Qinghai, Tibet's three provinces of the 23 counties, cities, and through the Qaidam Basin, crossing the Kunlun Mountains and Tanggula, along an average altitude of over 4000 meters, is currently the highest elevation in the world, the most difficult cable construction engineering, built after the opening of an initial long-distance telephone channels over 21,000 road.