On this day, 34 years ago, on April 29, 1991 (March 15, 1991, the world's first cable-stayed bridge-the Yangpu Bridge was started. Lin Yuanpei, chief engineer of the Shanghai Municipal Engineering Design and Research Institute of the completed Yangpu Bridge, pioneered the "Lin's Theory" when designing the Shanghai Yangpu Bridge, which solved the internal stress problem of long-span cable-stayed bridges, making the Yangpu Bridge the world's first cable-stayed bridge. Lin Yuanpei and Yangpu Bridge