Kilimanjaro is the tallest free-standing mountain on Earth. That means it isn't part of a chain of mountains - it sits on its own, rising straight up from flat plains. From the bottom to the top is nearly 5 kilometres of climbing, all in one giant slope.
It actually has three peaks, because it is really three old volcanoes joined together: Kibo (the highest and the one with the snow), Mawenzi, and Shira. Kibo has not erupted for around 360,000 years. It is now classed as 'dormant' - sleeping, but not gone forever.
Climbing Kilimanjaro is like walking through five different climates one above the other. At the bottom you start in warm farmland. Then come thick rainforests where monkeys live. Higher up, it becomes open moorland with strange giant plants. Higher still is a freezing rocky desert. At the very top, there are glaciers.
Around 35,000 people try to climb Kilimanjaro every year. They walk for about a week, sleeping in tents. The most magical moment is the final night: climbers start walking at midnight in the freezing cold so they can reach the summit at sunrise, when the whole of East Africa lights up below them.