The Durand Line is located in South Asia and serves as the international border between Afghanistan and Pakistan. Originally established in 1893 during the British colonial era, it is roughly 2,640 kilometers (1,640 miles) long and stretches from the border with Iran in the west toward the border with China in the east. Pakistan recognises the line as its legal international border, but Afghanistan has historically refused to recognise its legitimacy. The line crosses through rugged terrain, including the Hindu Kush mountains, the Khyber Pass, and the Sulaiman ranges. Pakistan started to erect a fence in 2017, which cuts through traditional Pashtun tribal lands and parts of Balochistan, placing ethnic groups on both sides of the frontier.