The waters around the small Cos­ta Rican island of Cocos are teem­ing with sharks, bring­ing with them poach­ers look­ing to snip off a few fins to sell. How­ev­er, thanks to the thank­less efforts of local rangers, many of the ille­gal shark hunters have been stopped, leav­ing behind nets, ropes and buoys that have been col­lect­ed to cre­ate a ram­shackle bridge across the Genius Riv­er on the island itself.