Tucked behind the Great Mosque of Salé, accessed by a small wooden door on a back street, the Medersa Abu al-Hassan is a jewel-box Merinid Qur'anic school built between 1333 and 1341 by sultan Abu al-Hassan Ali. It is the kind of building you can walk past three times before noticing — there is almost no signage — and the kind of building you should never miss once you do notice it. The whole school is tiny: a single square courtyard, two galleries of student cells on the upper floors, a prayer hall on the axis opposite the entrance, and a stair up to a narrow roof terrace.

The decoration is what makes the visit. The courtyard is clad waist-high in original zellige, and above that in deeply carved cedar beams and stucco bands of cursive inscription. The mihrab in the prayer hall is calligraphed in cut plaster rather than paint, the level of workmanship Moroccan craftsmen reached when the Merinid dynasty was at its cultural peak. Everything is scaled for one person at a time — the school never housed more than a couple of dozen students at once — which gives the visit a privacy you do not get at the more famous Merinid medersas in Fez and Meknes.

Save energy for the roof. A steep narrow stair climbs to a tile-edged terrace with one of the best views in the Rabat–Salé pair: across the Salé medina rooftops, down the Bou Regreg estuary, and over the river to the Kasbah of the Udayas on the opposite bank. The ticket is around 20 MAD. Plan thirty minutes inside — the school is small. Late morning gives the best light down into the courtyard through the open roof; Fridays around midday it closes for prayer; Mondays it sometimes opens late. The medersa occasionally closes for extended restoration — ask your Rabat hotel before you cross the river.