This Hydraulophone is located outside the Ontario Science Centre. I would love to know more about how it works because it sure looks, and sounds, great. I wonder how they play it during those long Canadian winters? Hydraulophone video

Presently the world’s largest hydraulophone is the main architectural centerpiece out in front of the Ontario Science Centre, one of Canada’s landmark architecture sites. It is also Toronto’s only freely accessible aquatic play facility that runs 24 hours a day. (Wikipedia)

Learn more about the Ontario Science Centre

Update:
Check out Matthew’s comments below for a lot more information. (PDF links)