The Velodrome — one of the most iconic and sustainable buildings ever built for an Olympic Games — contains the indoor cycling track. It was built to hold 6,000 people and keep them cool this summer with a completely natural ventilation system using outside air. That’s right; no air conditioning required. In addition, the Velodrome uses natural lighting during the day to supplement fluorescent lighting, saving a lot of energy. Did we mention it collects rainwater for its main water usage with its sloped roof? Savvy indeed.