Chadar is the name given to an old winter trade route linking Leh with Zanskar, in India Himalaya. The route follows frozen Zanskar river, and so it is "open" only during the winter months when the thick ice covering the river makes the walk possible. In fact, this is the only way to reach remote Zanskar villages in winter, when the snow blocks the roads and high passes. The river never freezes completely, though, and the journey is not an easy one! These days Chadar is an increasingly popular trekking route, and a number of groups do it every season. I did the trek in winter 2009, with Joel Schone of Project Himalaya.