We live in a consumer world and so that we don't forget it, advertisers wallpaper our cities and highways with banks of billboards.
Researchers at Lima's University of Engineering and Technology have come up with a billboard with a difference.
Using a system with condensers and filters, it traps the humidity in the air and extracts the water vapor to then produce around 96 liters of drinking water per day.
The public can then help themselves to it for free.