On this day, 28 years ago, on September 16, 1997 (August 15, 1997 in the lunar calendar), the entire Lanxila (Lanzhou-Xining-Lhasa) communication optical cable project was paved. On September 16, 1997, after more than two months of hard work by more than 20,000 officers and soldiers from the Lanzhou and Chengdu Military Regions, the entire line of Lansila communication optical cable line, a key national communications project, was laid 25 days earlier than originally planned. It was highly praised by the Ministry of Posts and Telecommunications and the Ministry of Communications of the General Staff Headquarters. The Lanzhou-Xining-Lhasa optical cable project has a total length of 2739 kilometers. It passes through 23 counties and cities in Gansu, Qinghai and Xizang provinces, passes through the Qaidam Basin, crosses the Kunlun Mountains and Tanggula Mountains. The average altitude along the route is more than 4000 meters. It is currently the highest altitude and the most difficult to construct in the world. It can provide more than 21,000 long-distance telephone routes in the early stages of completion and opening.