Engineer Guillermo D. Christy shows his hand stained with rust after touching a steel pillar installed inside the Aktun Tuyul cave system to support a part of the Maya Train track, on the outskirts of Playa del Carmen, Mexico, Sunday, March 3, 2024. Construction of the Maya Train is rapidly destroying much of the hidden underground world of caverns and sinkhole lakes, known as cenotes, already under threat by development and mass tourism. (AP Photo/Rodrigo Abd)