Bhutan's northern region consists of an arc of Eastern Himalayan alpine shrub and meadows reaching up to glaciated mountain peaks with an extremely cold climate at the highest elevations. Most peaks in the north are over above sea level; the highest point is -tall Gangkhar Puensum, which has the distinction of being the highest unclimbed mountain in the world. The lowest point, at , is in the valley of Drangme Chhu, where the river crosses the border with India. Watered by snow-fed rivers, alpine valleys in this region provide pasture for livestock, tended by a sparse population of migratory shepherds.