Would we have "Back to the Future" without Steven Spielberg?

Without his mentorship of director Robert Zemeckis, there's a very possible alternate reality where Marty McFly never got in that DeLorean.

Since becoming one of the most successful filmmakers in Hollywood with "Jaws," Spielberg has helped greenlight dozens of movies just by signing on as a producer.

He's been instrumental in talking talent into projects (like the "Men in Black" stars), giving expert advice, and shepherding movies that might never have gotten made, like Clint Eastwood's "Letters From Iwo Jima" and the films funded by his Shoah Foundation.

Here are some of his best "producer only" movies.

"Back to the Future 30th Anniversary Trilogy" is available to own now on Blu-ray & DVD.