Vertical garden at CaixaForum square, Paseo del Prado, Madrid. Created by Patrick Blanc, this 78-foot (24-meter) tall living wall contains 250 species of plants that survive on sunlight and water and no soil. Since its creation, the wall has changed dramatically. The original simple latticework interspersed with struggle seedlings is now a lush, green landscape on the side of a building. To get a first-hand look at it, head to 36 Paseo del Prado the next time you’re in Madrid.