Living root bridges

In the depths of northeastern India, one of the wettest places on earth, bridges aren’t built – they’re grown.
The living bridges of Cherrapunji, India are made from the roots of the Ficus elastica tree. This tree 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.

via Living Root Bridges
http://rootbridges.blogspot.com/