One of only two mosques in Morocco open to non-Muslims (the other being the Hassan II mosque in Casablanca), the Tin Mal Mosque is a worthwhile and historic visit despite its distance away from the main tourist trail. Deep in the High Atlas, Tin Mal was the seat of the Almohad empire when the mosque was built in 1156. The mosque would later serve as the model for the famous Koutoubia Mosque in Marrakech.
My friend and I took taxis to Talat N'Yacoub and then walked another hour or so along the road to the town of Tin Mal (I think a bus also takest the roughly 2-hour scenic drive from Bab Erob grand taxi station in Marrakech and may go all the way to Tin Mal). We arrived before the guide who waits at the door (bring a few dirhams for entry) and so we waited on the back side where we could peek in from a window. Around noon it opened and we were able to head in and immerse ourselves in the history and endless arches from just about every angle it seemed. While the minaret is missing, the original wooden doors do remain and can be found in one of the corners once inside. Afterward, head over to Chez Abdou for a delicious Berber omelette or mint tea before heading back.