Over the past 50 years, hockey has changed dramatically.
The biggest changes have been in the landscape of the game as what was once a six-team exclusive club is now a 30-team extravaganza.
Orr not only transformed the Bruins from the cellar-dwelling team they were in the early- and mid-1960s to one of the NHL's most exciting and popular teams, he also changed the way defensemen played the game.
Orr was the first defenseman who would join the attack whenever he had the opportunity. His offensive abilities were so spectacular that he is widely considered the most gifted player of all time, although we admit that Wayne Gretzky's backers could at least make a plausible argument.
However, Orr's speed, defensive strength and intelligence put him at the top of the defensive mountain, both of the all-time list and those who played in the past 50 years.
Note: This list has a has a heavy Bruins' tilt, but how could it not? Just as the list of all-time great baseball players is dominated by New York Yankees—Babe Ruth, Lou Gehrig, Joe DiMaggio, Mickey Mantle and Yogi Berra—the list of the top defensemen is dominated by Bruins.