Toward the east , the city ends in a plain that meets the Sierra Nevada , with its two extinct volcanoes, Ixtacihuatl ( 17,342 feet ) and Popocatepetl ( 17,883 feet ), which were once a familiar sight from Mexico City but are now usually obscured by pollution.
Nearby are two volcanoes that can only be seen from the city on days when wind has cleared out the pollution.