High altitude refers to locations that are significantly above sea level, typically starting at around 2,400 meters (7,874 feet). At these elevations, the air pressure decreases, leading to lower oxygen levels. This can affect human physiology, making it harder to breathe and causing symptoms like headaches and fatigue. High altitude environments are often found in mountainous regions, such as the Himalayas or the Andes. These areas can also experience unique weather patterns, including colder temperatures and increased UV radiation. Many plants and animals have adapted to survive in these challenging conditions, showcasing the diversity of life at high elevations.