An ultra-prominent peak, or Ultra for short, is defined as a mountain summit with a topographic prominence of or more. There are approximately 1,515 such peaks on Earth. Some are famous even to non-climbers, such as Mount Everest, Aconcagua, and Denali (the top three by prominence), while others are much more obscure. Some famous peaks, such as the Matterhorn and Eiger, are not Ultras because they are connected to higher mountains by high cols and therefore do not achieve enough topographic prominence.