" Most of the world’s mountain ranges have been thrown up by the jostling and collision of the continental plates. Thus, for example, the Alps were created when the Adriatic Plate (which carries Italy on its back) was driven into the Eurasian Plate. The oldest mountains are those which are now the lowest, for erosion has had time to reduce them. The blunted, rubbed-down spine of the Urals, for instance, speaks of great age. So too do the rounded forms of the Scottish Cairngorms. Perhaps surprisingly, among the youngest mountains on earth are the Himalaya, which began to form only 65 million years ago, when the Indian Plate motored northwards and smashed slowly into the Eurasian Plate – ducking underneath it and then butting it five-and-a-half miles upwards into the air. Compared to the earth’s venerable ranges, the Himalaya are adolescents, with sharp, punkish ridges instead of the bald and worn-down pates of older ranges. "
― Robert Macfarlane , Mountains of the Mind: A History of a Fascination