Dhaka, March 22 -- It was 1957. A handful of Baum families left behind their old settlement and walked into the deep hills, beyond roads and beyond reach -- into a forest that would become both their refuge and their responsibility.

From Darjeeling Para at the foot of Keokradong, the country's second-highest peak, it took more than three hours of treacherous trek to reach their new home.

At the foothills of Keokradong, in Ruma Sadar Union, the terrain is a mix of soft, slightly salty rock and scattered stones. At a particular time of year, the mineral-rich rock produces a crust on which grass and vines sprout. Wild deer, boar, and other creatures are drawn to these natural growths.

In the Baum language, the salty soft rocks are called ...