Guardian: One by one, the tribal leaders of the Brazilian Xingu took to their feet, wearing yellow and red feather headdresses and clutching thick wooden clubs and spears. Having travelled for days to reach the gathering in the isolated village of Mrotidjam, the Xikrin Kayapó elders stepped forward to address their visitor, a man they knew simply as Camerón. “If they build this dam, our children will die,” said one, his eyes painted a fiery red with seeds from the urucum tree. “There will be no …