This was the test case for York Universitys new 'green' design agenda. As the first green building in Ontario, it demonstrated for the first time that a sustainable approach could succeed in a cold climate. Undergraduate and graduate labs, classrooms, offices, and a 950-seat lecture hall complex are housed in a highly functional, flexible building that provides a transparent, animated and welcoming presence on Campus Walk, the University's main pedestrian thoroughfare. Every aspect of the building minimizes environmental impact: a highly efficient passive ventilation system, organized around 'thermal chimneys' and a bamboo-planted atrium; recyclable and low embodied energy materials; sun-shading devices on the south and west faades; and an extensive planted roof. CSEB has an energy consumption at 50% below conventionally built equivalents. The project was completed with Busby Perkins + Will.