Taiwan has an area of 35,808 square kilometres (13,826 sq mi), with mountain ranges dominating the eastern two-thirds and plains in the western third, where its highly urbanized population is concentrated. The capital is Taipei, which, along with New Taipei and Keelung, forms the largest metropolitan area of Taiwan. Other major cities include Kaohsiung, Taichung, Tainan and Taoyuan. With 23.57 million inhabitants, Taiwan is among the most densely populated countries in the world.