Kabul is the capital of Afghanistan and its largest city, located in the eastern section of the country. It is also a municipality, forming part of the greater Kabul Province. According to estimates in 2015, the population of Kabul is 4.635 million, which includes all the major ethnic groups. Rapid urbanization had made Kabul the world's 75th largest city.
Kabul is located high up in a narrow valley between the Hindu Kush mountains, with an elevation of 1,790 metres making it one of the highest capitals in the world. The city is said to be over 3,500 years old, mentioned since at least the time of the Achaemenid Empire. It is at a strategic location along the trade routes of South and Central Asia, and a key location of the ancient Silk Road. It has been part of the Achaemenids followed by the Seleucids, Mauryans, Kushans, Kabul Shahis, Saffarids, Samanids, Ghaznavids, Ghurids, Khwarazmians, Qarlughids, Khaljis, Timurids, Mughals, and Hotaks, until finally becoming part of the Durrani Empire in 1747. Kabul became the capital of Afghanistan in 1776, during the reign of Timur Shah Durrani, the son of Ahmad Shah Durrani.