Basically, with a POD after 1900, can you make Canada a great power, rivaling or even surpassing the U.S., the British Empire, or other great powers? The economy, population, and military of Canada should be significantly "better" than OTL (pretty obvious this scenario).
After the Second World War (if there is one) or something along the lines of it, I'd want to see the U.S., the U.S.S.R., and Canada to be regarded as the "superpowers" of the world.
I don't care what you change, just make it plausible and make it contribute to Canada becoming a great power.
(Points for whoever can make Canada carve out its own power bloc, like the Warsaw Pact or NATO. More points to whoever can make Canada have their own very good designs in a military aspects, like the Avro Arrow, and actually use them/sell them to other nations.)