Mount Everest is generally regarded as the highest mountain in the world when height is measured by elevation of its summit above mean sea level. Its summit reaches approximately 8848.86 metres above sea level according to the elevation established by Nepal and China in their joint announcement in 2020. Mount Everest lies in the Himalayas on the border between Nepal and the Tibet Autonomous Region of China.
In Nepal it is commonly called Sagarmatha, while in Tibet it is known as Chomolungma or Qomolangma. The mountain is part of the Mahalangur Himal subrange and is surrounded by other extremely high Himalayan peaks. The statement that Everest is the highest mountain in the world therefore refers specifically to the standard sea level measurement, which is the most widely used definition of highest mountain.
Mount Everest is located at approximately 27.9881 degrees north latitude and 86.9250 degrees east longitude, although exact coordinate values vary slightly according to mapping conventions. Its summit is near the boundary between Nepal and Tibet, and the international border follows the mountain ridge in this region. Everest is part of a complex Himalayan landscape created by the collision of the Indian and Eurasian tectonic plates. The Himalayas continue to rise tectonically, while erosion, weathering, glaciers and gravitational processes remove material.
The resulting landscape is extremely high and rugged. Everest itself is composed of layered geological rocks, including sedimentary and metamorphic materials, and its upper regions contain limestone and other rocks that have been uplifted from geological environments that existed long before the present Himalayas formed.
The modern English name Mount Everest honours George Everest, a nineteenth century Surveyor General of India. The mountain was previously known within the British survey system as Peak XV before the name Everest was officially adopted in the nineteenth century. The naming history is more complex than the modern English name suggests because the mountain already had established names in regional languages and cultures. Sagarmatha is the official Nepali name, while Chomolungma or Qomolangma is the Tibetan name. The coexistence of these names reflects the mountain's geographical position and cultural history. Place names can carry historical, linguistic and political significance, so using the name Everest does not eliminate the importance of its established regional names.
Everest's elevation is not a completely immutable number because mountain summits are natural surfaces that can change through geological uplift, erosion, earthquakes, snow and ice accumulation and measurement methodology. The 8848.86 metre figure announced jointly by Nepal and China in 2020 represents a modern determination that incorporated surveying and positioning techniques and included the summit snow and ice cap according to the agreed methodology.
Earlier official measurements produced somewhat different values because surveying methods, reference systems and treatment of summit snow and ice differed. Modern elevation measurements can use GNSS, geodetic observations, gravimetric information and other surveying methods. Therefore, small differences among published heights do not necessarily indicate that the identity of the highest mountain has changed.
Everest's extreme elevation produces severe environmental conditions. Atmospheric pressure decreases substantially with altitude, reducing the amount of oxygen available for human respiration. Temperatures are extremely low, winds can be severe, and weather can change rapidly. Glaciers, snowfields, crevasses, avalanches and unstable rock create significant mountaineering hazards. The summit lies within the high altitude zone commonly called the death zone, where the human body cannot maintain normal physiological function indefinitely without supplemental oxygen and acclimatisation. Climbers attempting Everest must manage altitude, cold, weather, route conditions, equipment, logistics and emergency risks. The mountain is therefore not simply a high point on a map but a highly demanding physical environment.
Everest has been a major focus of mountaineering since the early twentieth century. British expeditions investigated and attempted routes before Edmund Hillary of New Zealand and Tenzing Norgay of Nepal reached the summit on 29 May 1953. Their successful ascent became a landmark in mountaineering history. Since then, thousands of summit attempts have been made, with climbing routes established from both the Nepalese and Tibetan sides. Commercial expeditions have expanded access but have also generated debates about crowding, environmental impacts, waste, risk management and the sustainability of tourism. Everest remains scientifically important for studying high altitude environments, glaciers, climate change, geology and atmospheric conditions.
The phrase highest mountain requires a measurement criterion. Everest is highest above sea level, but other mountains can exceed it under other definitions. Mauna Kea in Hawaii rises higher from its submarine base to its summit than Everest does from sea level to its summit, although much of Mauna Kea lies below the ocean surface.
Chimborazo in Ecuador has a summit farther from Earth's centre because Earth is an oblate spheroid and the equatorial region bulges outward, placing Chimborazo near the Equator at a greater radial distance from the planetary centre. These distinctions demonstrate why statements about the highest mountain should specify the reference used. In ordinary geographic usage, highest mountain means highest summit elevation above mean sea level, making Everest the standard answer.
Mount Everest is therefore the highest mountain in the world by the conventional and widely accepted criterion of summit elevation above sea level, with a jointly established 2020 elevation of 8848.86 metres. Its significance extends beyond its numerical height because it is a product of Himalayan tectonics, a culturally important named landscape, a major mountaineering destination and a challenging high altitude environment. Understanding the term highest requires attention to the reference surface and measurement method. Everest holds the standard global height record above sea level, while alternative measurements such as base to summit or distance from Earth's centre identify different mountains for different reasons.
