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.
The BBC’s Will Ross in Lagos says it is not clear whether all houses in the area are to be destroyed.
Makoko is one of Nigeria’s best known slums. Many residents are fishermen and some have migrated from neighbouring Togo and Benin.
It featured in the 2010 BBC film Welcome to Lagos, which angered the Nigerian government, accusing the film-makers of showing Nigeria in a negative light.
A letter was served on residents last week, giving them 72 hours to vacate their properties.
Several told the BBC they did not know where they and their families would sleep.
Our correspondent saw men using machetes to chop down the stilts of the wooden homes, while police watched from nearby boats.