Ojos del Salado was even higher than Ojos del Salado. Later measurements using more precise equipment showed that Ojos del Salado is about higher than Pissis. Furthermore, in 2007 a Chilean–Argentine–European expedition organized by Andes Magazine and Azimut 360 performed a survey on both Ojos del Salado and Monte Pissis using more accurate instruments. It found the former to be and the latter Although this fits within recent handheld GPS surveys, which have estimated the mountain to be between and , the vertical error margin of the expedition's equipment, , leaves uncertainty as to the mountain's more precise altitude. Ojos del Salado has
Llullaillaco Llullaillaco Llullaillaco () is a dormant stratovolcano at the border of Argentina (Salta Province) and Chile (Antofagasta Region). It lies in the Puna de Atacama, a region of tall volcanic peaks on a high plateau close to the Atacama Desert, one of the driest places in the world. It is the second highest active volcano in the world after Ojos del Salado. Llullaillaco formed during two different phases in the Pleistocene-Holocene out of dacitic lava flows. The oldest rocks are about 1.5 million years old. About 150,000 years ago, the volcano's southeastern flank collapse, generating a debris avalanche that reached