The most important mosque in the city is the Great Mosque of Sidi-Uqba also known as the Great Mosque of Kairouan. It has been said that seven pilgrimages to this mosque is considered the equivalent of one pilgrimage to Mecca. After its establishment, Kairouan became an Islamic and Qur'anic learning centre in North Africa. An article by Professor Kwesi Prah describes how during the medieval period, Kairouan was considered the third holiest city in Islam after Mecca and Medina. Today, many consider the city as the fourth holiest in Islam.
Judaism, no longer prevalent in the city, has an illustrious history in Kairouan, particularly in the early Middle Ages. Rabbeinu Chushiel, his son Rabbeinu Chananel, and R. Nissim Ben Jacob (R. Nissim Gaon) were all from Kairouan and Rabbi Isaac Alfasi studied there, as did many other great rabbis. The rabbinical students of Kairouan are a major part of the transmission of the Oral Law from Babylonia to Spain. Kairouan was thus the first major centre of Jewish learning outside of Babylonia and Eretz Yisrael. In memory of Sufi saints,Sufi festivals are held in the city
