Sousse is ideally placed for day trips to some of Tunisia's best sights. Kairouan (55 km west) is Islam's fourth holiest city and home to the Great Mosque, one of the oldest in North Africa — the ochre-coloured old town is stunning and the mosques and medersa are open to non-Muslim visitors. El Jem (70 km south) has a Roman amphitheatre of extraordinary scale — the third-largest in the Roman world — rising incongruously from the flat Tunisian plain.
Monastir (20 km south by Metro du Sahel) has another Ribat, the mausoleum of president Habib Bourguiba, and a pleasant old town. Mahdia (60 km south) is a quiet Tunisian port town with a long medina on a narrow peninsula, mostly untouched by mass tourism.
