A less common transportation method.

When the War-Khasis tribe needs a new bridge to cross one of the many criss-crossing rivers of the cherrapunji region, they don’t build one. They grow it. The root bridges, some of which are over a hundred feet long, take ten to fifteen years to become fully functional, but they’re extraordinarily strong – strong enough that some of them can support the weight of fifty or more people at a time.

Cherrapunji is credited with being the wettest place on earth, and The War-Khasis, a tribe in Meghalaya, long ago noticed this tree and saw in its powerful roots an opportunity to easily cross the area’s many rivers. Now, whenever and wherever the need arises, they simply grow their bridges.

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 has come to be known as the “Umshiang Double-Decker Root Bridge.”

In order to make a rubber tree’s roots grow in the right direction – say, over a river – 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. Given enough time, a sturdy, living bridge is produced.

The root bridges, some of which are over a hundred feet long, take ten to fifteen years to become fully functional, but they’re extraordinarily strong – strong enough that some of them can support the weight of fifty or more people at a time.

[youtube]http://www.youtube.com/watch?v=hEI_GRjvDPk[/youtube]

Because they are alive and still growing, the bridges actually gain strength over time – and some of the ancient root bridges used daily by the people of the villages around Cherrapunji may be well over five hundred years old.

Link – via rootbridges