Raqqa, known as the 'City of Palaces,' served as the capital of the Abbasid Caliphate under Harun al-Rashid in the 8th century. The city features remnants of the Great Mosque of Raqqa and ancient Islamic fortifications including the famous Baghdad Gate. Despite recent challenges, Raqqa maintains its significance as a historic center of Islamic learning and culture along the Euphrates River.