Ah yes, it's for the environment, no really!The authorities in Rio de Janeiro are to build walls around many of the Brazilian city's slums, in what they say is a bid to protect the rainforest.
City officials insist the project will stop the shanty towns, or favelas, from expanding into the countryside.
Concrete walls 3.5m (10ft) high are due to hem in about 40 favelas by the end of the year, at a cost of $17m (£12m).
Human rights groups say the walls are designed to segregate the city's poor from its wealthy residents.
Residents 'to benefit'
The president of the Rio's public works department, Icaro Moreno, visited the Dona Marta district on Tuesday.
Pointing to the lush green forest on the other side of the wall, he said that each year more of the environment was being lost, and that something had to be done.
"We are simply asking residents to continue to build within the limits we have established," he said.
"We have already seen a lot of environmental damage and, quite frankly, many of these homes have been built in high-risk flood areas, so it will benefit the residents as well."
Critics say the move will only serve to emphasise the deep divisions in Brazil between rich and poor.
Human rights groups have suggested that Rio's wealthy residents living in high-rise apartments do not want to be reminded of the conditions in which their neighbours live.
But the authorities say they will make the conditions better inside the walls, while protecting the wildlife outside.
If you're that worried about the environment and the wildlife why not wall off a real problem source, your bloody ranchers?
I'm wondering how long before the people trapped in these slums will require passes to leave their walled off areas. Where it is sooo easy to forget about them...