New Delhi, June 7 -- We had been walking for over an hour-down a steep, moss-slicked staircase cut into the hillside of Rangthylliang, a remote village in Meghalaya's East Khasi Hills. The forest thickened with each step-bamboo groves pressed in close, their trunks darkened by rain, the sound of a stream somewhere below. And then, around a bend, it appeared. A bridge. Not built-grown.

Braided roots-some as thick as a thigh, others slender and pale-stretched 53 metres across a river gorge, from one bank to another. They coiled and twisted through the air like something alive. This was no ordinary structure. It was a living root bridge-a marvel of bioengineering shaped by hand over decades, even centuries, using the aerial roots of the Fic...