The span (Jembatan Akar means “root bridge”) was first conceived of in 1890 by a local teacher who wanted his students from a village across the river to have an easier time getting to his classes. To start the bridge, he put a bamboo frame in place and began wrapping the ever-growing aerial roots of the large banyan trees on either side of the water along the frame. Ever so slowly, the bridge began to take shape.

This bridge has a length of 25 metres (82 ft) and a width of 1.5 metres (4 ft 11 in) with a height from the surface of the river of about 3 metres (9.8 ft).
The process of weaving the roots into the bridge took about 26 years and the bridge was put into use in 1916. Since then, the bridge has been reinforced with wooden planks and metal cables and become more stable through each year as well as becoming stronger year after year as the massive roots of the still-living trees continue to grow.
Today another bridge has been built nearby for people on both sides of the river to use, but this tree roots bridge always attracts many curious tourists flocking to admire as well as try to cross. This unique and one-of-a-kind bridge.
According to Wikipedia and atlasobscura.com