Built in the 11th and 12th centuries and extended in the 1500s, the walls in the Nigerian city of Kano are among of the most interesting examples of ancient fortifications in Africa. Because of the earthen building materials used and the lack of a conservation movement until very recently, the walls of Kano are not nearly as intact as most of the other examples on this list. However, sections are still well preserved, and the walls have been submitted to UNESCO as an important natural and cultural heritage site, the first step in becoming a World Heritage Site. Kano was, and still is, a major stop along the trans-Saharan trade route. The Kurmi Market, first established in the 1400s and still used today, is a living example of the colorful past when goods from all across Northern and Western Africa were traded in its narrow lanes.