"Jurassic Park" is a 1993 movie adaptation of Michael Crichton's best-selling novel. It sparked a movie franchise that has 4 blockbuster titles under its belt. Though, it would seem that the movie originally had a different ending scene planned as a picture of a storyboard was released by Jurassic Time on Facebook. It depicts the final helicopter rescue scene differently and slightly alters how the movie ended compared to what was used in the final cut of the movie.
The storyboard details how the character of Alan Grant and the rest of the survivors are racing to the helipad in a jeep while being chased by the T-Rex. Grant manages to help the kids into the helicopter before he gets in himself. The T-Rex lunges and nearly bites Grant's leg off but instead bites off a piece of the helicopter. After a few moments of struggling, the helicopter flies to safety. According to Screen Rant, this film was presumably never filmed and/or left on the cutting room floor.
In the version of the movie that was released in theaters, Alan Grant and the rest of the characters were chased around the Visitor's Center by three Velociraptors. They were able to narrowly escape, with the help of the T-Rex, and join John Hammond who was waiting outside in a jeep before driving to a helicopter which flew them to safety.
One of the most powerful images in the movie can be seen in the last few scenes. As the cast escapes the Visitor's Center, the T-Rex lets out another mighty roar as a banner that reads "When Dinosaurs Ruled the Earth" falls in front of it. According to the synopsis of iMDB, "The ending scene perfectly captures the spirit of the film in portraying dinosaurs as some of the most magnificent creatures to ever walk the Earth."
While the final cut's ending was able to send this powerful message through that single scene, using the intended ending "could have been far more intense because of the sheer scale of the action," as per Cinemeblend's report. Though, a T-Rex chase scene did take place in the movie's final cut; it happened in the middle of the movie after the T-Rex' initial attack on the characters.