The Bullit Centre in Seattle may not be considered as the most aesthetically designed building but it is, however, considered to be the most sustainable commercial building in the world. It is an office building that uses solar panels and runs on 100% renewable energy. It is also energy efficient as it uses natural light and utilizes natural ventilation. In addition, it has its own water and waste management systems. It also promotes activity from the users via the inviting stairwells. The existence of the bike garages is not only space efficient but also promotes a healthier life and environment.
Read more about it here: Bullit Centre Office Space Design: Clean and Green