Next door to the Bird’s Nest, and affectionately referred to as the “Water Cube”, this USD 200 million Australian-designed structure is regarded as the perfect yin to the Bird’s Nest’s yang – a comforting "curvy" contrast to the rigidity of the stadium. Drawing inspiration from nature, the bubble-wrapped exterior answers an old physics problem about how to fill space most efficiently (the answer: two bubbles of equal volume but different shape). Bubbles also make for sleek earthquake-proof construction, without the need for obtrusive concrete or structural beams. Presuming that they get their daily wipes, this translucent covering of plastic “pillows” (100,000 square meters in total) helps reduce the amount of energy needed for interior heating and lighting, while allowing in more light and heat than glass would. Other green features include the recycling of 10,000 tons of rainwater collected by the outer surface and roof. Post-Olympics, the Cube has opened the warm-up pool for public swims, while renovations will dismantle temporary seats to create an aquatic center and water theme park. RMB 200 (adults), RMB 160 (children from 1.2m-1.4m), kids under 1.2m free.