Reference
In the movie, there’s a scene when Lt. Dan tells Forrest that the day he works on a shrimp boat will be the day he becomes an astronaut. This is a very subtle nod to the book that Gump really does become an astronaut. Weirdly enough, Hanks and Gary are reunited in Apollo 13 the very next year, where they both play astronauts.
Extras
We all know that Forrest Gump used special effects to create some of the noteworthy scenes. The shot of Forrest looking out to the Washington Monument is one of the most famous examples of CGI. They used over 1,500 extras and positioned them in different places in different clothes. Then, by using technology, they duplicated them and made 1,500 people look like 150,000. Even though this is common today, back then it was revolutionary.