Julien Millot and Tancrede Melet walked a line on the Vanoise Express cable car between the snowy peaks of the French Alps. The line itself was 60 metres long but only 2.5 centimetres wide and it was strung between two cable cars 380 metres above the ground, which Millot and Melet crossed with nothing but a small rope attached to a harness to stop them falling to a certain death.