The city of Madrid, Spain is spending millions to expand existing parks, while covering as many roofs and walls as possible with greenery in order to decrease rising summer temperatures in the city. Twenty-two vacant lots will also be turned into urban gardens while paved squares will become parks that can suck up rainfall. Planting gardens on roofs, and adding plants on outdoor walls, helps insulate buildings so they can save energy, and helps reduce street noise. But it also helps bring down local temperatures by shading pavement and by releasing evaporated water that can create clouds.