The Tilicho Lake side hike is an option to add about 27km and 2-3 days onto your Annapurna Circuit trek. And it is some of the most beautiful scenery and challenging trekking you will day along your full expedition. The final climb covers about 1000 meters of gravelly trail that gets more and more quiet the higher you go. One tip from many is while the morning is cold, the wind at the top is colder. It also picks up later into the morning and early afternoon, most people plan to be off the top of the mountain by no later than 10AM for that reason.