The Steel Curtain's famed front four were:
#75 "Mean Joe"(Charles Edward) Greene - defensive tackle, 1969-1981 (1969 Defensive Rookie of the Year; 1972 & 1974 Defensive Player of the Year; NFL 1970s All-Decade Team; Hall of Fame)
#68 L. C. Greenwood - defensive end, 1969-1981 (NFL 1970s All-Decade Team)
#63 Ernie Holmes - defensive tackle, 1972–1977
#78 Dwight White - defensive end, 1971–1980
Today, only Joe Green survives.
(http://ts2.mm.bing.net/th?id=H.4557614322680753&w=221&h=174&c=7&rs=1&pid=1.7)