Certainly, Nolan Ryan was no stranger to smithing game-defining moments over the course of his 27-season-long career. On this day, Ryan made Major League Baseball history when he threw his 4,000th career strikeout. The historic whiff came when Ryan was pitching for the Houston Astros and was achieved on New York Mets outfielder Danny Heep. To this day, only four MLB pitchers have ever crossed this mind-boggling threshold.