The Original Six era ended in 1967 when the NHL doubled in size by adding six new expansion teams. The six existing teams were formed into the newly created East Division, while the new expansion teams were formed into the West Division. The NHL continued to expand, adding another six teams, to total 18 by 1974. This continued expansion was partially brought about by the NHL's attempts to compete with the World Hockey Association, which operated from 1972 until 1979 and sought to compete with the NHL for markets and players. Bobby Hull was the most famous player to defect to the rival league, signing a $2.75 million contract with the Winnipeg Jets. The NHL became involved in international play in the mid-1970s, starting with the Summit Series in 1972 which pitted the top Canadian players of the NHL against the top players in the Soviet Union, which was won by Canada with four wins, three losses, and a tie. Eventually, Soviet-Bloc players streamed into the NHL with the fall of the Iron Curtain in 1989. (more...)