A look at huge sinkholes.
Physical weathering includes the action of ice and frost and the effect of plants and animals. When water gets into crack in rock, it freezes and expands. This expansion can expansion can exert a force up to 635 kg/cm2 (1400lb/sq in). With repeated freezing and thawing cracks gradually enlarge to the point at which pieces of rock break off. The process, known as ice- or frost-wedging, is most pronounced on mountains, where the daily cycle of freezing and thawing, even in summer, creates large accumulations of rock rubble, called talus or scree, around the base of steep slopes.
Around 40 million years ago, the Australian-Indian plate was drifting northwards towards the Eurasian plate. Ancient rock on the sea floor between them was gradually pushed upwards to form the beginnings of the Himalayas and the Tibetan plateau. Eventually the Indian plate moved under the Eurasian plate, pushing up the mountains further still.