Wow, one of the coolest things I’ve seen in a long time is the California Academy of Sciences in San Francisco’s Golden Gate Park. The building is an outstanding example of sustainable design and “green” architecture, featuring things such as a “living roof”, a natural cooling system (no A/C), solar panels, insulation made from old blue jeans, rainwater catchment, and the use of re-used / recycled materials in the construction. The museum also has a rainforest (filled with plants, butterflies, birds, fish, etc.), a huge aquarium and living reef, and the world’s largest digital planeterium.