Hundreds of city officials from across Africa have gathered in South Africa for a conference to consider new models for African cities.

The seventh Africities Summit opened in Johannesburg, South Africa's largest city, on Sunday. Key topics for the five-day meeting include climate change and how to build environmentally sustainable cities. Security in cities will also be discussed, in the wake of attacks in Paris and Mali's capital Bamako. Existing challenges like poverty, housing and transportation will also be discussed.

The meeting has been held in various African cities every three years since it was launched in 1998 in Abidjan, the largest city of Ivory Coast.