Part of Hall of Planet Earth.
AMNH/R.Mickens
Like icebergs or ships in water, continents and their mountains “float” on the denser mantle. High mountains such as the Himalayas are balanced by a keel, or root, that penetrates deeper into the mantle. As the mountains are worn down by erosion, the weight of the crust is reduced, and the mountains rise. The balance between the mountains’ massive weight and their buoyancy in the mantle is one of the factors determining the height of the range.