The name “Ansoo” comes from its tear-like shape (the Urdu word Ansoo means teardrop). This lake also resembles Human Eye with central ice land resembling Iris of Human Eye and a ridge resembling Eyebrow becoming even more prominent when ice melts on the Eyebrow in summers
Ansoo Lake is a high-altitude lake (elevation 16,492 feet or 5,027 metres) in the Kaghan Valley in the Mansehra District of the Khyber-Pakhtunkhwa province of Pakistan. It is near Malika Parbat in the Himalayan range.
This lake can be reached by two different routes. First one is short but steeper trek from Saiful Mulook Lake. Start the trekking from Saiful Malook cross it move toward Malka Parbat. It takes more than 12 hours for a round trip to Ansoo lake starting from lake Saiful Mulook. The trek is covered with snow in most parts of the year. The best time to trek is from July 10 to August 15. The optimal time to set off for the lake from Saiful Mulook is around 06:00 in the morning. Horses can also be hired from the Lake Saiful Mulook along with a guide who will take you to Ansoo Lake. It costs almost PKR 1200-1500 per horse and PKR 1000 additional for the guide but one still has to walk more than 35% of the distance by himself. This trek can be further divided into two part. First half, which is towards Saiful Malook, is valley along the river and it goes up to Malika Parbat base camp. Second half is steeper starting from Malika Parbat base camp and ends with Ansoo Lake. This part is all about climbing on the mountain.
Second trek to reach Ansoo Lake starts from the village Mahandri, which is 40 km south to Naran Village, and it goes through Manoor Gali and Kach Gali. This trek takes at least three days of 12 hour trekking to get to Ansoo Lake. Steepness of this trek may be the same as of other one but travel in the valley is lot more. This gives an opportunity to camp along the rivers, in jungles, on the top of mountains and in abandoned towns.
Both of above mentioned treks run in opposite direction from Ansoo lake and are connected via mountains top forming half circle 300–400 feet above the lake waters. From this altitude, there is an amazing vista of lake on one side and top of Malika Parbat and beautiful skyline of high altitude mountains covered with snow on the other side. There is no risk free way to reach lake waters because it lies in the crater with steep, snow covered walls. There is no apparent drainage of lake water and no one ever tried to explore it because of its dangerous approach and limited resources in that area.
Wondefurl explanation of facts available here.