'I didn't even know this was humanly possible': the woman who can descend into the sea on one breath

Scientists once thought humans could swim to a maximum depth of 30m on a single breath. Amber Bourke has gone deeper than 70m and physiology alone can't explain why Meet more superhumans in our series Ten years ago, Australian Amber Bourke was in her early 20s and backpacking through Egypt when she discovered something astonishing about herself. In a little village on the Sinai peninsula she came across a place that taught "free diving" - underwater diving without any breathing apparatus - and d...