This monumental gate once spanned the canal. Built by the first Marinid sultan after the alert of 1260, Bab Mrisa shows techniques that are still very close to those used on the Almohad gates in Rabat. Flanked by two narrow towers, it features a Gothic arch of magnificent scope (although embankments have taken away part of its height) and a décor with sculpted inscriptions and floral interlacing.