Originating in crowded cities like Hong Kong and Tokyo, green walls developed as a method to save the world from the poor air quality and other environmental issues associated with crowded cities. Usually made up of plant-filled panels, green walls may be attached to any existing structure. While any type of plant may be chosen, choices such as ferns directly impact the reduction of air pollution. Plants that combine beauty with purpose are favorites. Green walls are easy to maintain. Watering can be provided through the building’s plumbing system, and gardening chores, like weeding, are not required. The walls also provide natural cooling to the structure. The landscaping of green walls are meant to provide beauty as well as the potential benefit to save the world.