Viacrucis participants march through Chahuites, Mexico. (Photo by author)

MEXICO CITY — Ciudad Tecún Umán is sweltering. All of the town’s households and its handful of ramshackle cantinas still use wood-burning stoves, their sweaty attendants braving the compounded afternoon heat. The smoke trails out into the few dusty streets, unpaved, potholed and barely stretching to the edge of the Rio Suchiate, which divides Tecún…