I think this is brilliant. Just goes to show that the best solutions are often the simplest
In the slums of Manila, an innovative project is shedding light on the city's dim and dreary shanties. Plastic bottles jut from the roofs, bringing light to the dark dwellings below. The technology is as simple as it could be. Each bottle contains water and bleach. When placed snugly into a purpose-built hole in the roof, the home-made bulb refracts and spreads sunlight, illuminating the room beneath. Eco-entrepreneur Illac Diaz is behind the project.
Also featured on BBC Newsround. watch here