A glass-bottom platform that takes visitors a towering 400 metres above ground opens in China. Yuming Woo reports. At 400 metres above the ground, this glass-bottom platform isn't a relaxing spot for those with a fear of heights. While some were visibly nervous, others were relaxed. Owners of the viewing platform say it's currently the biggest in the world. The platform is located in Shilinxia Scenic Area, 50 miles east of Beijing.