<Li> Cotopaxi, 5,897 m (19,347 ft) </Li> <Li> El Altar, 5,320 m (17,454 ft) </Li> <Li> Illiniza, 5,248 m (17,218 ft) </Li> <Li> Pichincha, 4,784 m (15,696 ft) </Li>

What are the three sub regions of south america what is significant about the atacama desert