Opened in 2006, the Four Seasons Centre for the Performing Arts was specifically built for opera and ballet performances with an emphasis on outstanding acoustics. The building includes a number of one-of-a-kind features such as a massive, German-made glass façade and the longest free-spanning glass staircase in the world. Modeled after traditional European opera houses, the main auditorium features five-tiers and horseshoe design. The seats were 3-D designed and tested to ensure unobstructed views. The downtown Toronto building is home to both the Canadian Opera Company and the National Ballet of Canada and offers an annual series of free lunchtime and evening concerts.