Engineer Guillermo D. Christy walks past a steel pillar filled with concrete installed to support a part of the Maya Train track inside the Aktun Tuyul cave system 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)