Paul Walker was synonymous with fast cars and pretty women - having starred in the "Fast & Furious" franchise and alongside some of the prettiest actresses in the world including Jessica Alba.

But there was more to the movie star than his good looks and charm. Walker, who died in a car crash Saturday in Los Angeles at just 40 years old, had a strong passion for marine biology.

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In fact, that's what the Glendale, Calif., native studied in college before hitting it big in roles like "Varsity Blues" and "She's All That."

In 2010, Walker got to live out a life-long dream for National Geographic's "Expedition Great White," where he spent days as part of a crew catching and tagging Great White sharks off the coast of Mexico.

"The sea is just a big mystery," he told fabela iMag during interviews for "Fast & Furious Five." "There are things that are more alien in the ocean than I think are alien in space. It seems like every other day, there's a new discovery. You look at it and you're like, 'Really!' … Things that are so bizarre … it's mind blowing."

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It was this enthusiasm that brought Walker back this past July to join Discovery's Shark Week for an August special, "Spawn of Jaws," that looked at the life cycle of Great Whites.

Aside from his passion for the ocean and it's mysterious creatures, Walker was father to a 15-year-old daughter Meadow from a past relationship with Rebecca McBrain.

Walker gushed to People magazine in 2011 about his growing daughter.

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"She's bloomed!" he said about his daughter, who moved from Hawaii to California to be closer to her father. "She's a bit more like her mother, but she's also how I am innately. [Meadow]'s more of a free roamer and she appreciates the little stuff."

He added, " The trick is to just listen," when it came to relating to his teenage daughter.

Paul Walker, The Humanitarian

Off the set, Walker consistently used his celebrity to help others in times of crisis. At the time of his death on Saturday, he was taking part in a charity event for his nonprofit group Reach Out Worldwide, which was trying to help those affected by the typhoon in the Philippines.

In early 2010, Walker visited Chile after a magnitude 8.8 earthquake struck the area, triggering a tsunami and ravaging the country.

"You know, I have a lot of friends that surf and travel down here in Chile," he told a local Chile TV station of why he decided to come and help. "They told me and said, 'Man, it's going to be bad.' The thing's that incredible to me, is the morale [down here], the spirit. It's strong!"

Only months later, Walker and his organization traveled to Haiti to help build shelters and provide medical help for those struck by their own earthquake. IV bags, tubing and other supplies were brought to orphanages and refugee camps in support.

For why Walker started this organization, Reach Out Worldwide's website says, "While part of a relief team responding to the massive earthquakes that devastated Haiti on January 12, 2010; Actor/Producer Paul Walker saw a gap between the availability of skilled resources and the requirement for such personnel in post-disaster situations. Following the trip he contacted a group of his friends to assist him in forming ROWW with the purpose of filling this unmet need."

(Photo Credit: Starsurf / Splash News)