Throwback: 'Indiana Jones and the Last Crusade' Celebrates 25 Years

"Germany has declared war on the Jones boys…" It's been 25 years since Indiana Jones and the Last Crusade first hit theaters in the summer of '89 – and 30 since Indiana Jones and the Temple of Doom arrived. Both blockbuster sequels to Raiders of the Lost Ark hit theaters on May 23 and 24, respectively, and in celebration we've got vintage ET 1989 interviews with Harrison Ford and Sean Connery, who discuss why the father-son dynamic made Last Crusade so appealing -- and get candid about why Temple of Doom failed to connect with audiences.

"There's a vulnerability that everyone has with their father," Harrison told ET. "It's unlike the vulnerability that you have with everybody else, and I think it's part of everybody's experience. There's a real ring of truth to the relationship between Indiana Jones and his father."

"Well that was the kind of nucleus of what it was all about, for me anyway," added Connery. "Not so understanding with their children, as Americans are – more kind of dismissive."

Last Crusade, Steven Spielberg and George Lucas' third entry in the Indiana Jones series, gave the franchise a shot in the arm by introducing Connery as Indy's dad, Dr. Henry Jones Sr. The plot is set in motion when he goes missing. Although the two haven't spoken in 20 years, Indy sets out to find his dad, only to become embroiled in a thrilling race to find with Holy Grail before the Nazi party can get their hands on it for the Fuhrer – and get the power for world domination.

Related Video: 'Gremlins' Star Reflects on an '80s Classic

The first follow-up to 1981's Raiders of the Lost Ark, Indiana Jones and the Temple of Doom, was actually a prequel. Despite its huge box office success, the film was widely criticized for being too violent and mean-spirited, especially for its PG rating. The Spielberg-produced Gremlins also came out that summer two weeks later with similar complaints from parents, prompting the Motion Picture Association of America's ratings board to create the PG-13 rating that year.

"All of our ambitions became more focused on what we wanted out of this third film," Harrison told ET. "Part of it was a degree of regret about how the second one phrased itself. Although very successful as a film, I think it perhaps is a little too strong, there's perhaps a little bit too much violence, a little bit too much mysto-crypto kind of stuff in it for my particular taste. I was pleased to see us go back to the ambitions and the style of the first film."

Five years later, Last Crusade healed wounds and soothed bad memories of Temple of Doom with its return to a lighter, more comic-book style adventure with another rousing John Williams score. A rewarding depth of character, great chemistry and snappy interplay between Ford and Connery redeemed the series, which arguably plunged to a new low with 2008's playful but over-the-top Indiana Jones and the Kingdom of the Crystal Skull.