Frenchman Julien Millot walked across the two inch wide wire of the Vanoise Express cable car which runs in front of Mont Blanc in the French Alps.
A highline is a type of tightrope walk which is done on a slack line strung between two points.
It was inspired by artists who walked on cables that were fixed between points thousands of feet in the air.
This cable way linked Las Arcs, Peisey-Vallandry and la Plagne and was designed by Jean-Charles de Castelbajac.
The pair are part of a group called Skyliners that travel the globe doing various stunts and extreme sports such as rock climbing, tightrope walking and base jumping.