The country Mongolia was like a buffer state between Russia and China. By definition, a buffer state is a country that's in between two countries or any powerful countries. Both countries sometimes come into agreement of occupying a certain part of the buffer state and can also cause war.
The Himalayan mountain range and Tibetan plateau have formed as a result of the collision between the Indian Plate and Eurasian Plate which began 50 million years ago and continues today.