I never did much bridge design, but I remember something about HS-20 being the design standard. Some agency decided that trucks get modeled like the graphic below and that bridges shouldn’t fall down when the trucks drive over them.
I guess the tribesmen in Cherrapunji, India didn’t get the memo. They live in the rainiest place on earth and have lots of rivers to cross. They also have rubber trees that will grow roots horizontally when trained. So when they want a bridge, they just grow it.
I’ve never seen anything like this. I enjoyed the concept and thought you might too. You can learn more and see additional photos here.