This glacial lake hides a dark secret - This Himalayan lake hides quite the dark secret. A chilling discovery was made in the 1940s, but it wasn't until the 21st century that the mystery was solved. Or was it? Browser through this gallery and draw your own conclusions.

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Roopkund - Roopkund, also known as Skeleton Lake or Mystery Lake, is a glacial lake in India.

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Location -

The lake is located near Wan village in the Chamoli district of Uttarakhanin, in the Himalayas.

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Location - Skeleton Lake is a high-altitude lake located at around 5,029 meters (16,499 feet) above sea level.

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Snow - The lake is covered in snow for about eight months of the year.

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Lake discovery - In 1942, a British forest guard made a macabre discovery: a frozen lake full of human bones!

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Skeletons - But it was about to get even more bizarre. As the ice melted during summer, the lake unveiled even more skeletons.

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British investigation - WWII was underway at the time and the British government suspected these were the remains of Japanese soldiers who died en route to a land invasion.

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Japanese soldiers - The British government sent a team of investigators to Roopkund. More shock: they came to the conclusion that the bones were too ancient to be from Japanese soldiers.

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Mystery - Many theories arose at the time, including a landslide, an epidemic, or even ritual suicide as the cause of all those deaths.

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Expedition - In 2004, an expedition to Roopkund was organized with the express goal of solving the mystery.

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Old bones - It was concluded that the skeletons were dated to around 850 AD.

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Remains - The local weather conditions made it possible for some hair, flesh, and even clothes of the victims to remain preserved.

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DNA testing - Two distinctive groups of people were identified from the remains. One was a group of closely related individuals, who could have been a family or a tribe.

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DNA testing - The other group was composed of individuals from 200 years ago with genetic affinity with east mediterraneans.

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Who were they? - It is believed that the bones belong to pilgrims who were crossing the mountains with the help of local guides.

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How did they die? -

Despite the many theories put forth, there was only one common denominator in all skulls: they were cracked.

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How did they die? -

The cracks on the skulls were deep and short. The shoulders also presented wounds. All of these seemed to have been inflicted from above.

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How did they die? - The conclusion was that hailstones were the cause of death. Violent and sudden hailstorms supposedly hit the group and killed them.

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Hailstorms - Being unable to hide, pilgrims and locals alike were hail-stoned to death.

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Ancient song -

The lyrics to an ancient Himalayan folk song tell the story of a goddess who beame so enraged when her sanctuary was damaged by outsiders that she killed them with hailstones as hard as iron.

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Nanda Devi Raj Jat - The Nanda Devi Raj Jat is a pilgrimage and festival dedicated to the worship of goddess Nanda Devi.

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Nanda Devi Raj Jat - Roopkund is on the pilgrimage route of Nanda Devi Raj Jat.

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Local legend - Legend has it that once a king took some dancers to Roopkund, but heavy snowfall transformed them into skeletons and stones.

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Local legend - Another folk story mentions King Yasodhwal's pregnant wife. It goes that while giving birth, her placenta flowed down to Roopkund and killed everyone there.

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Roopkund Trek - This is one of India's most popular trekking routes.

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Trekking route - The trek can be demanding, but the surrounding landscape is absolutely breathtaking.

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Getting there - A three to four-day trek is required to get to Skeleton Lake.

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