Active Popocatepetl volcano (5.452 meters) with a bit of smoke rising above the smog and clouds of Mexico City in the Valley of Mexico. "Popo" is Mexico's second highest mountain. To it's right is Iztaccihuatl, an extinct volcano. They are a mere 70 km (44 mi) to the southeast of Mexico City and is often visible from the capital, depending on atmospheric conditions. Mexico.