Explanation:

Roopkund (locally known as Mystery Lake, Skeletons Lake) is a high altitude glacial lake in the Uttarakhand state of India. It lies in the lap of Trishul massif and is famous for the hundreds of human skeletons found at the edge of the lake. The area is uninhabited, in the Himalayas at an altitude of 16,470 feet (5,020 m).

A shallow lake, having a depth of about two metres, Roopkund has attracted attention because of the human skeletal remains that are visible at its bottom when the snow melts. Researchers have concluded that the skeletons are the remains of people killed in a sudden, violent hailstorm in the 9th century. Because of the human remains, the lake has been called Skeleton Lake in recent times.