Speleologist - or cave expert - Roberto Rojo knows the jungle like his own backyard, but what he is currently seeing on Mexico's Yucatán Peninsula is unlike anything he's ever witnessed before. A long, deforested swathe now cuts through the rainforest south of the popular holiday resort of Cancún on the tip of the southeastern peninsula. Thousands of large construction pillars penetrate the ground every 15 metres in anticipation of the Tren Maya, a new railway line being created to ferry million