Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia. It has a 1,046 kilometres (650 mi) coastline along the Arabian Sea and Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. Tajikistan also lies very close to Pakistan but is separated by the narrow Wakhan Corridor. Thus, it occupies a crossroads position between South Asia, Central Asia and the Middle East. The region forming modern Pakistan was at the heart of the ancient Indus Valley Civilisation and then later was the recipient of Vedic, Persian, Indo-Greek, Turco-Mongol, Islamic and Sikh cultures. The area has witnessed invasions and/or settlements by the Indo-Aryans, Persians, Greeks, Arabs, Turks, Afghans, Mongols and the British.