Keelung locates at the northern Taiwan, with mountains surrounding on three sides, while Donghai (The Eastern Sea) in its north front. Serving as a natural harbor with the immense water, Keelung has its bay cut into downtown deeply. Within the city are much more slopes than planes, and moreover, the protective Keelung Islet and Hoping Islet screen on both sides of the water. These factors mentioned above have contributed to this natural and strategically difficult point, which combines roles of commercial, military, and fishing harbor, yet most importantly, keeps guard at the gates of the whole Taipei area.