The ancient Maya made salt by boiling brine in pots over fires in salt kitchens, according to a paper by Louisiana State University’s Professor Heather McKillop. The first documented record of salt as an ancient Maya commodity at a marketplace is depicted in a mural painted more than 2,500 years ago at Calakmul, a UNESCO World Heritage site in the Yucatan Peninsula in Mexico. Image credit: Rogelio Valencia, Proyecto Arqueológico Calakmul. The first...