The California Academy of Sciences in San Francisco has unmatched green credentials. A roof top garden called Living Roof, insulates the building. The solar canopy has 60,000 photo voltaic cells. The insulation in the walls is recycled denim. The disposable plates and forks in the cafeteria are compostable. All waste bins come in threes. The one that is generally called ‘trash’ carries a powerful message in its label. Brilliant.