In the depths of North-Eastern India, in one of the wettest places on earth, bridges aren’t built – they’re grown.
The living bridges of Cherrapunji, India are grown from the roots of the Ficus elastica tree. A species of Indian rubber tree with an incredibly strong root system, the Ficus Elastica produces a series of secondary roots from higher up its trunk and can comfortably perch atop huge boulders along the riverbanks, or even in the middle of the rivers themselves.
Cherrapunji is known as the wettest place on earth, and the War-Khasis, a local tribe, have long ago noticed the characteristics of this tree and saw in its powerful roots an opportunity to cross the area’s many rivers with ease. Whenever and wherever the need arised, they have simply grown their bridges.
The War-Khasis have used many different strategies in order to make rubber trees’ roots grow in the right direction. Sometimes, the roots of the trees are simply pulled, tied, twisted, and encouraged by hand to merge with each other, until, over time, they form the desired architectural structure. At other times, they are made by creating scaffolds out of wood and bamboo, and then training the young roots out across these temporary structures, replacing the more perishable elements many times as they rot in the intense monsoon seasons.
In some places, such as around the village of Nongriat, the Khasis use betel nut trunks, sliced down the middle and hollowed out, to create root-guidance systems. The thin, tender roots of the rubber tree, prevented from fanning out by the betel nut trunks, grow straight out. When they reach the other side of the river, they’re allowed to take root in the soil. Over time, a sturdy, living bridge is produced.
It takes take ten to fifteen years for the root bridges, some of which are over a hundred feet long, to become fully functional, but they’re extraordinarily strong – often strong enough to support the weight of fifty or more people at a time.
As they are alive and still growing, the bridges actually gain strength over time. It is not surprising, therefore, that some of the ancient root bridges used daily by the people of the villages around Cherrapunji today may be well over five hundred years old.
One special root bridge, believed to be the only one of its kind in the world, is actually two bridges stacked one over the other and is known as the Umshiang Double-Decker Root Bridge.
via Atlas Obscura, Root Bridges
