More about this programme: http://www.bbc.co.uk/humanplanet During monsoon season the Mekong swells to 20 times its normal volume, which brings more fish to the Khone Falls but makes them much harder to catch. Sam Niang, a local fisherman, came up with a plan to get to the best fishing perch. He built a tightrope across the rapids out of old cable and bits of rope.