Billboard in Lima conjures drinkable water 'out of thin air'
22 March 2013 Last updated at 19:10 GMT
An unusual billboard outside the Peruvian capital which collects humidity from the surrounding air and filters into drinkable water is proving popular with locals who are often forced to draw dirty water from wells.
The people behind the innovation claim it can provide water for hundreds of families each month.
BBC Mundo's David Cuen reports.