Arbil (also written Erbil, or Irbil) ( Kurdish: ھەولێر Hewlêr; Akkadian: Arba-ilu; Arabic: اربيل‎ Arbīl; Aramaic: ܐܪܒܝܠ Arbela; Sumerian: Urbilum; Turkish: Erbil) is the fourth largest city in Iraq after Baghdad, Basra and Mosul. The city lies eighty kilometres (fifty miles) east of Mosul, and is the capital of Iraqi Kurdistan. Urban life at Arbil can be dated back to at least 6000 BC, and it is one of the oldest continuously inhabited cities in the world. At the heart of the city is the ancient Citadel of Arbil. The Hurrians were the first to establish Urbilum and expand their rule to the rest of Northern Mesopotamia. Afterwards, The city has been under the rule of many regional powers since that time, including the Assyrians, Babylonians, Persians, Arabs, and Ottomans. The city's archaeological museum houses a large collection of pre-Islamic artifacts, and is a center for archaeological projects in the area.