Popocatepetl (the Smoking Mountain) and Iztaccihuatl (the White Lady) are adjacent volcanoes at the south end of the Valley of Mexico.
The Aztecs believed the two volcanoes were lovers that could not bear to be out of each others sight. Iztaccihuatls profile looks like a reclining women. The names of the volcanoes summit reflect the legend: Cabeza (head), Pecho (breast), Rodillas (knees), and Pies (feet). From Vitaliano (1973).
Photo by Steve O'Meara of Volcano Watch International.
See also these published sources: