A trek that takes one from the parbati valley in kullu to the pin valley in spiti across the 5319mts pin parbati pass, from the lush temperate forest of the former to the barren, cold desert landscapes of latter.One needs to be extremely fit and very well prepared for this trek as there is absolutely no habitation along its entire length. Trek commences from Gwacha, a tiny hamlet high up the parbati valley, past manikaran.from there the route follows the parbati river upstream for three days  with night halts at khir ganga(hot springs),Pandupul(steeped in the pandava mythology) and mantalai,. One passes through amazing forests of betula (bhojpatra) and walnut, make a few risky river crossings on wiresuspended baskets ! only persons you may now meet are the migratory gujjars and gaddis.Treeline is crossed just before pandupul. mantalai is a huge glacial lake at 4116mts. It is the source of the parbati. It is an awesome sight with glaciers flowing down to it from allsides. from here it is another two days  of hard climbing to the pin parbati pass.The saddle of the pass is covered with a permanent ice-field and must be crossed with great care as it is criss-crossed with crevasses. fifth day's campsite is far below the pass, on the banks of the infant pin river at 4200mts. it takes two more days to reach the first village on the pin side-mudh. The entire stretch from the pass  to mudh is in the pin valley national park which provides a haven for many rare species-snow leopard,spiti wolf, ibex and ghural. A road has now reached mudh, 12kms. beyond which are sagnam/mikkim(3600mts) a twin village located at the confluence of the pin and the paraiho. from here it is a spectacular drive of 35kms. to kaza, and then on to manali over the kunzum and rothangpasses