The world’s oldest university in Morocco’s Fez

The world’s oldest university in Morocco’s Fez was once kept under lock and key — four of each, to be exact — in what CNN calls “a 16th century security system.” Behind the copper door that in yesteryear required the presence of four different keyholders to unlock are some of the most valuable manuscripts in the world, including a 9th century Quran and one of the oldest known accounts of Prophet Muhammad’s life. The works at al-Qarawiyyin University (all 30,000 of them) remain as valuable as ever, but access to them is now controlled by a single curator and keyholder (watch, runtime 1:09).