On August 2, 1944, American warplanes breached the walls of Tengchong. Six B-25s from the 22nd Bomb Squadron flew through the valley at tree-top level, sending their 1,000-pound bombs into the ancient stone wall. The bombs opened up five breaches, the largest of which was just over fifteen feet wide. Chinese troops charged forward, but the Japanese fought back savagely. It was days before the Chinese were able to move through into the city and months before they finally pushed out the Japanese.