Many migrant farmworkers in Spain say they can't afford housing, so they live in makeshift plastic housing near the farms where they work. Local governments have tried to remove these informal settlements and relocate people to shelters far from the farms — but they keep building back.
Picture a skyscraper filled with greenhouses and hanging plants, that's precisely Professor Dickson Despommier's plan ?a vertical farm, for a world that is rapidly running out of space to grow food.