Nigerian authorities knock down water slums
17 July 2012 Last updated at 23:28 BST
The authorities in Nigeria have started knocking down slum dwellings built on the lagoon in its biggest city Lagos.
Dozens of shacks built on stilts have been demolished in Makoko, where wooden canoes are a common form of transport.
A state official in Lagos told the BBC that all illegal buildings in the water would be demolished.
Will Ross reports.