The snow and ice-clad peak of Pico de Orizaba (also known as Citlaltepetl) boasts a summit elevation of 5,675 m (18,619 ft) above sea level, making it the highest peak in Mexico and North America?s highest volcano. It is also one of three volcanic peaks in Mexico – together with Popocatepetl and Iztaccihuatl – that retain summit glaciers. Pico de Orizaba is part of the Trans-Mexican Volcanic Belt that extends roughly east-west across Mexico. The last recorded eruption took place in 1846; while the volcano is considered dormant at present, geologists continue to investigate the potential hazards associated with a renewal of activity. Shadows accentuate several features of the Pico de Orizaba stratovolcano visible in this photograph from the International Space Station. The 300-meter-deep summit crater is clearly visible against surrounding ice and snow cover at center. Several lava flows extend down the flanks of the volcano, made readily visible by prominent cooling ridges along their sides known as flow levees. One of the most clearly visible examples is located on the southwest flank of the cone. The extinct Sierra Negra volcano to the southwest has a summit elevation of 4,640 m (15,223 ft) above sea level; while not as lofty as Pico de Orizaba, it is also one of Mexico?s highest peaks. Image courtesy of NASA.