Kairouan is an important Islamic city in Tunisia, and is said to be the fourth holiest city in the Muslim world and the oldest Muslim city in the Maghreb. The city was originally set up as a military outpost, but quickly became a center of Islamic learning. The most important site in Kairouan is the Great Mosque of Okba, which dates to around AD800. There is a large courtyard with pillars surrounding the minaret and prayer area. This mosque may be visited by non-Muslims, but they may not enter the prayer area. A visit to Kairouan would not be complete without exploring the UNESCO world heritage site of the Ancient Medina. As you travel here you will enjoy the narrow streets, colorful shops, and many monuments important to Muslims.