Kabul is situated in the eastern part of the country, above sea level in a narrow valley, wedged between the Hindu Kush mountains along the Kabul River. Immediately to the south of the old city are the ancient city walls and the Sher Darwaza mountain, with the Shuhadayi Salihin cemetery behind it. A bit further east is the ancient Bala Hissar fortress with the Kol-e Hasmat Khan lake behind it.