This bilboard is for the University of Engineering and Technology of Peru (UTEC) in Lima, Peru. The air there is incredibly humid, and this billboard uses that humidity to produce drinking water from thin air. Many people in Lima have limited access to clean drinking water.
Infographic: The secret life of drinking water. Water scarcity will be one of the defining features of the 21st century. The U.N. predicts that by 2025 two thirds of the world's population will suffer water shortages. Here CNN takes a look at what we do with the water we can drink. Find out more at unwater.org. Produced by Mairi Mackay, CNN @mairicnn and George Webster, for CNN @George_CNN. Designed by Matt Barringer, CNN @eskimomatt Sources: World Health Organization, UNHabitat.