As UFC 137 quickly approaches, fans across the globe patiently wait for the drama-filled fight card that will take place on Saturday, Oct. 29th.
With Georges St-Pierre out with a knee injury, the main card will be headlined by former UFC champion BJ Penn, who will square off with dangerous Nick Diaz.
While UFC 137's fighters have made it to the highest stage in mixed martial arts, there was that one career-defining moment that changed their careers forever.
The following slides display the career-defining moment for each fighter on the main card at UFC 137.
Lets take a look.