Translations of hieroglyphs on the staircase of a pyramid in Guatemala reveal details of a superpower struggle between two city-states at the peak of the Mayan civilisation. The 1300-year old hieroglyphs support theories that the Mayan world was riven by battles between two major powers, rather than smaller-scale clashes between multiple rival dynasties. "It's rare that you find a new monument and it fills in such a large blank spot about the history of a region," says Arthur Demarest, an anthropologist at Vanderbilt University, Tennessee, who has led research at Dos Pilas in northern Guatemala, where the staircase was found....