Nepal, home of the world's highest mountain, has Kathmandu as its capital.
Kathmandu sits in the Kathmandu Valley of central Nepal and is the country's largest city, political center, and main cultural hub. The city is also a major gateway to the Himalayas, including Mount Everest, whose southern climbing routes begin in Nepal.
Mount Everest is the world's highest mountain above sea level, reaching 8,848.86 meters. Its Nepali name is Sagarmatha, while the Tibetan name is Chomolungma. The mountain lies on the Nepal–China border, so Everest is not entirely inside Nepal, a detail that sometimes causes confusion.
The city is commonly spelled Kathmandu in English, although the question's “Katmandu” is a recognized variant spelling. Kathmandu's name is linked to Kasthamandap, a historic wooden pavilion whose name combines Sanskrit words meaning “wood” and “pavilion.”