The surface of the Earth consists of a series of huge tectonic plates. These plates move slowly about and sometimes collide with each other. When this happen, the edges of the plates are pushed up and the layers of rock crumple and fold. Over millions of years, the folds form chains of mountains.
Theory has it that the Indian subcontinent was not a part of mainland Asia during the time of Pangaea eons and eons ago. The Indian tectonic plate has been crashing into the Eurasian plate for more or less the last 50 million years, creating enormous uplift force and in the process forming the Himalayan mountain ranges where the world's tallest mountains are located. The collision between the two huge plates still continues to raise the Himalayas by about five millimeter per year.
