Wikipedia
Ngazargamu
Gazargamo was the capital of the Bornu Empire from ca. 1460 to 1809. Situated 150 km west of Lake Chad in the Yobe State of modern Nigeria, the impressive remains of the former capital city are still visible. The surrounding wall is 6.6 km long and in parts it is still up to 5 m high. The town was built by Mai Ali Gaji (1455–1487) after the final defeat of the Dawudid branch of the Sefuwa ruling dynasty.
The city was then an important centre for trade and learning, at its height home to around 20,000 inhabitants.
In 1809, after several years of indecisive warfare, Gazargamo was besieged and destroyed by Malam Zaki, in the Fulani jihad.