Roopkund Lake, also known as Mystery Lake, is in the eastern part of Chamoli District
. It is an oval shaped lake situated at an altitude of 5029 m and 16,000 ft above the sea level. The lake covers the regions of Garhwal and Kumaon
and lies at the base of the Trishul Peak
. The lake is named Mystery Lake because of the remains of the skeletons of people and animals that lie on the banks. During the summer months, when ice melts, the skeletons are clearly visible through the water. The lake remains frozen for rest of the year.