The eight-thousanders are 14 mountains recognised by the International Mountaineering and Climbing Federation (UIAA) with summits that exceed 8,000 metres (26,247 ft) in elevation above sea level and are sufficiently independent of neighbouring peaks as measured by topographic prominence. There is no formally agreed-upon definition of prominence, however, and at times the UIAA has considered whether the list of 8,000-metre peaks should be expanded to 20 peaks by including the major satellite peaks of the canonical 14 eight-thousanders. All of the Earth's eight-thousanders are located in the Himalayan and Karakoram mountain ranges in Asia, and their summits lie in the altitude range known as the death zone, where atmospheric oxygen pressure is insufficient to sustain human life for extended periods of time.