Right in the heart of the medina, Ez-Zitouna is the oldest mosque in Tunis and one of the most important in the country. Built in the 7th or 8th century, it’s a massive complex with a beautiful central courtyard. Non-Muslims aren’t really allowed inside the prayer hall, but you can still step into the courtyard and admire the architecture. They'll provide you with a scarf and proper coverings if needed.