The incredible landscapes of the Yucatan peninsula in Mexico provide the backdrop for The Serpent King. If you would like to find out all about this amazing place - the forests, cenotes, ruined cities and wildlife, do watch Mexico: Earth's Festival of Life (Episode 2) on BBC1. I'm watching it now, and reliving my research trip to Mexico two years ago. It even features Calakmul, the setting for Cleo and Ryan's adventures. You can hear howler monkeys and see divers exploring cenotes jsut like the one where Cleo and Ryan find the White Finder Tree - the sacred secret world of Xib'alb'a.