Who is the top hero in Canada?????

Well, if it is up to me, I will pick Wayne Gretzky, the greatest hockey player of all time. And you know how big the game is in Canada. : )

But on a serious note, to satisfy the condition of "having changed the world", Dr Fredrick Banting should be a good choice. He discovered insulin as cure to diabetics, and won the first ever Nobel prize for Canada.

Also, Alexender Graham Bell, the inventor of telephone, is another option. The reason is obvious enough. One thing which may go against this pick though, is that Bell was not quite so "canadian". He actually born in Scotland, and only immgirated to Canada in his 20s.