The Karakoram is a mountain range spanning the borders of China, India, and Pakistan, with the northwest extremity of the range extending to Afghanistan and Tajikistan; its highest 15 mountains are all based in Pakistan. It begins in the Wakhan Corridor (Afghanistan) in the west and encompasses the majority of Gilgit-Baltistan (Pakistan) and extends into Ladakh (India) and the disputed Aksai Chin region controlled by China. It is the second highest mountain range in the world and part of the complex of ranges including the Pamir Mountains, the Hindu Kush and the Himalayan Mountains. The Karakoram has eighteen summits over height, with four of them exceeding : K2, the second highest peak in the world at , Gasherbrum I, Broad Peak and Gasherbrum II.