“Old Oyo in southwest Nigeria is a said to be the former city of Oyo (known as Oyo-Ile), which was deserted in the 18th century after a war with Hausa/Fulani raiders. The site lies within the confines of Old Oyo National Park, and on it are the ruins of buildings built by people who lived there in the past, such as the old palace compound, outer walls with ditches and a water reservoir. There are also wells, cisterns, and grinding hollows which are proof of an extensive past settlement. Within the park is also the famous Agbaku Cave, which served as shelter for the ancient warriors of the Oyo-Alaafin Kingdom during times of war.”
SOURCE: Culture Trip