This painting shows the pundit, Sarat Chandra Das, travelling incognito on a yak in 1879. He is crossing the Donkhya Pass in India at 18,000 feet (5,486m).

At the time, the British were desperate to find out more about the  lands beyond the mountains of Kashmir before the Russians advanced further into central Asia. The British could not go to Tibet themselves because their entry into the country was prohibited.

The British recruited, equipped and trained Tibetan looking Indians to explore and survey the forbidden lands for them. Sarat and others like him carried only basic instruments, and were under the constant threat of detection.

For over 20 years, the pundits undertook amazing journeys and brought back their findings for British map-makers and strategists.

The vital information that Chandra Das and the pundit known as "M H" recorded was all that was known about the approaches to Everest until the early years of the twentieth century.