High in the Himalayas lies Roopkund Lake, where a surprising event unfolds every summer. Hundreds of human skeletons emerge as the ice melts and accumulates in the banks. So, what's the mystery all about? Once believed to be the remains of people killed in a deadly hailstorm nearly 1,200 years ago, DNA and carbon-dating research revealed a far more complex story. Watch the video to know the whole story!