Kangchenjunga is 8,586 metres tall. That is nearly 10 times the height of the tallest building most people have ever seen. The air at the top is so thin that even strong climbers have to carry tanks of oxygen with them to breathe.
The Himalayas are the youngest big mountains on Earth - only about 50 million years old, which sounds like a lot but is young for a mountain. They were made when two giant pieces of the Earth's crust crashed together and pushed the land upwards. The mountains are still growing by a few millimetres every year.
The Himalayas run along the top of India like a giant wall. They include Mount Everest (the highest mountain on Earth) and over a hundred peaks above 7,000 metres. Many of India's biggest rivers start as melted snow up in these mountains and flow all the way across the country.
People who live in the Himalayan villages are some of the best mountaineers in the world. The Sherpa people, for example, grow up walking and carrying things at very high altitudes. Their bodies are extra good at using the thin mountain air, and climbers from all over the world rely on them as guides.