K2 (8,611 m) is the world's second-highest mountain, straddling the Pakistan–China border in the Karakoram Range. Nicknamed the "Savage Mountain," it's widely considered the toughest and deadliest 8,000er to climb — steeper, more technical, and less forgiving than Everest, with a death rate near 1 in 8 summits. This guide covers K2's height and location, climbing history from the 1954 first ascent to the 2021 winter ascent, the notorious Bottleneck, and recent 2025–2026 accidents on the mountain.