The mud-brick walls that ring Kano's Old City are among the most complete examples of pre-colonial African urban fortification still standing. Though much of the original 15th-century structure has crumbled or been built over, substantial sections remain — the most accessible is near the Kofar Mata Gate, where you can walk alongside walls several metres thick and several stories high, their surface baked to a deep terracotta by generations of Sahel sun.
Fourteen of the original 16 gates survive in some form. The most interesting to seek out are Kofar Mata (near the dye pits), Kofar Wambai (once the gate through which slaves were brought in from the south), and Kofar Na'isa, which retains some of its original mud-brick gatehouse architecture. Asking a local guide to walk you around the circuit takes two to three hours and reveals sections of wall that are entirely absent from tourist maps.