The NHL was established on Nov. 26, 1917, in Montreal. The puck dropped on the league's first games the following month. The NHL's member teams were constantly changing for the majority of the league's first two decades in existence.
But that revolving door stopped in the 1940s.
The same six teams made up the NHL from 1942 until the league expanded to 12 clubs in 1967. Those six franchises, known as the Original Six, are the Montreal Canadiens, Toronto Maple Leafs, Boston Bruins, Detroit Red Wings, Chicago Blackhawks and New York Rangers.