Empire, Songhai Empire, the Kanem Empire and the subsequent Bornu Empire. They built stone structures like in Tichit, but mainly constructed in adobe. The Great Mosque of Djenne is most reflective of Sahelian architecture and is the largest adobe building in the world. In the forest zone, several states and empires such as Bono State, Akwamu and others emerged. The Ashanti Empire arose in the 18th century in modern-day Ghana. The Kingdom of Nri, was established by the Igbo in the 11th century. Nri was famous for having a priest-king who wielded no military power. Nri was a rare African state which was a haven for freed slaves and outcasts who sought refuge in their territory. Other major states included the kingdoms of Ifẹ and Oyo in the western block of Nigeria which became prominent about 700–900 and 1400 respectively, and center of Yoruba culture. The Yoruba's built massive mud walls around their cities, the most famous being Sungbo's Eredo. Another prominent kingdom in southwestern Nigeria was the Kingdom of Benin 9th–11th century whose power lasted between the 15th and 19th century and was one of the greatest Empires of African history documented all over the world. Their dominance reached as far as the well-known city of Eko which was named Lagos by the Portuguese traders and other early European settlers. The Edo-speaking people of Benin are known for their famous bronze casting and rich coral, wealth, ancient science and technology and the Walls of Benin, which is the largest man-made structure in the world. In the 18th century, the Oyo and the Aro confederacy were responsible for most of the slaves exported from modern-day Nigeria, selling them to European slave traders. Following the Napoleonic Wars, the British expanded their influence into the Nigerian interior. In 1885, British claims to a West African sphere of influence received international recognition, and in the following year the Royal Niger Company was chartered under the leadership of Sir George Goldie. In 1900, the company's territory came under the control of the British government, which moved to consolidate its hold over the area of modern Nigeria. On 1 January 1901, Nigeria became a British protectorate as part of the British Empire, the foremost world power at the time. Nigeria was granted its independence in 1960 during the period of decolonization. Central Africa Archeological finds in Central Africa provide evidence of human settlement that may