Kufa, ten kilometres east of Najaf along the Euphrates, was the capital of Imam Ali's caliphate, and its Great Mosque is one of the oldest in Islam. Founded in the year 638, it has been rebuilt repeatedly, but the basic plan — a vast walled courtyard with arcaded prayer halls — preserves the form of the earliest Islamic mosques. For Shia Muslims this is the second holiest mosque in the world, after the Imam Ali Shrine itself.
Within the courtyard a series of small shrines mark spots of religious significance, including the prayer niches of the prophets Adam, Noah and Idris, and the house of Imam Ali. Pilgrims typically combine a visit here with the nearby Maslim ibn Aqeel shrine. Dress conservatively and expect to be searched at the entrance.