Activists in Mexico have published photos of steel and cement pilings from a government project that were driven directly through the roofs of sensitive limestone caves on the Yucatan peninsula. The network of caves, sinkhole lakes and underground rivers along Mexico's Caribbean coast are both environmentally sensitive and have been found to hold some of the oldest human remains in North America. President Andrés Manuel López Obrador had promised that part of his controversial $20 billion tourist train project, known as the Maya Train, would run on an elevated causeway support...