A massive mudslide struck the Gyirong Port on the China-Nepal border in China's Xizang Autonomous Region on August 26. As of 6 p.m. on August 29, the death toll had risen to 16, with well over 500 people listed as still missing. For days, rescuers have battled thick layers of mud and debris, roads swept away and treacherous terrain to reach the disaster zone. By land, water and air, hundreds of rescue personnel have pushed forward, searching for survivors, clearing access routes and restoring communications. Here's a look at the race against time to reach the heart of Gyirong Port, where the search continues and rescuers refuse to give up as long as there is still hope of finding survivors.