West Africa includes the Cape Verde Islands, Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, Mauritania, Niger, Nigeria, the island of Saint Helena, Senegal, Sierra Leone, Sao Tome/Principe and Togo.
The Republic of Mali is part of West Africa and has a varied geography. In the south and west are verdant river valleys while the north and east jut into the Sahara Desert. It is a French speaking nation though dozens of languages are spoken there. Islam was introduced in the 11th century and is the dominant religion.
The Federal Republic of Nigeria is the most populous nation in Africa and is home to some 500 ethnic groups (and languages) including the Yoruba people. Nigeria has a large Christian population concentrated in the central and southern regions and an equally large Muslim population predominantly in the north and southwest.