“Cobbled with volcanic stones in the 16th century, the streets of Tochimilco are exceptions to the rough village roads that would slow traffic in an evacuation. Hoping for enough warning to let people escape, engineers from CENAPRED, the National Disaster Prevention Center, watch for any ominous changes in the volcano’s shape. They anchor equipment high on the north slope, facing the sleeping volcano Iztaccíhuatl.”
—From “Popocatépetl: Mexico's Smoking Mountain,” January 1999, National Geographic magazine