This massive volcanic complex is the world's third highest active volcano, but remains largely unknown.  Cerro Tipas, also known as Cerro Walter Penk, is located immediately SSW of its better known neighbor, 6887-m-high Nevados Ojos del Salado, Earth's highest volcano.  The 6660-m-high summit of Cerro Tipas lies within Argentina, immediately south of the Chilean border.  The Tipas volcanic complex of craters, cones, lava domes and lava flows covers an area of 25 sq km.  It displays a youthful morphology, and its latest eruptions were considered by de Silva and Francis (1991) to be of Holocene age.