WULINGYUAN, China, July 30 (Reuters) - Straddled between two cliffs in China's Hunan province, a 430-meter glass-bottomed suspension bridge offers the world's highest bungy jump from a footbridge. Visitors to the Zhangjiajie Grand Canyon Glass Bridge can take a leap from a height of 260 meters, a stomach-churning way to take in the views of the surrounding Wulingyuan wilderness, a UNSECO World Heritage site.