Cayambe, which has a permanent snow cap, is a Holocene compound volcano which last erupted in March 1786. At , its south slope is the highest point in the world crossed by the Equator, and the only point on the Equator with snow cover. The ice cap covers an area of about and there are glaciers on the eastern flank descending to about , whereas those on the drier western flank reach about . The volcano and most of its slopes are within the Cayambe Coca Ecological Reserve.