Mexico’s outgoing leader has rapidly built a train system looping around the country’s southern Yucatan Peninsula. But the crown jewel of the populist’s presidency, meant to draw development into long-neglected communities, also runs over one of Mexico’s natural wonders: A fragile system of an estimated 10,000 subterranean caverns, rivers, lakes, and freshwater sinkholes. “That’s total ecocide," said one researcher staring into the destroyed remnants of a cave. (Photo: Rodrigo Abd)