The California Academy of Science green roof has several environmentally friendly features, as well as sustainable design. Renzo Piano was inspired by seven major hills of San Francisco, which typically refers to: Telegraph Hill, Nob Hill, Russian Hill, Rincon Hill, Mount Sutro, Twin Peaks and Mount Davidson. The living green roof was planted with 1.7 million California native plants. The museum's central piazza lies beneath a massive glass ceiling in the roof, which opens to allow cool night air to flow into the building below; by using this kind of natural ventilation instead of air conditioning to regulate interior temperature, the building becomes more energy efficient. Renzo Piano and SWA Group won the American Society of Landscape Architects (ASLA) Award in design in 2009.