It's been two decades, and still, the waves from the tsunami that was "Waterworld" have not receded.

Released 20 years ago this week (on July 28, 1995), the post-apocalyptic epic about the survivors of a drowned Earth became known as one of the most bloated flops of all time. That reputation wasn't really fair (the movie eventually broke even), but it was the then-most expensive movie ever made.

For a year before the film's release, stories leaked out about the waterlogged production's near-disastrous setbacks and its ego clashes between star Kevin Costner and his hand-picked director, Kevin Reynolds. Punsters were calling the movie "Fishtar" and "Kevin's Gate." By the time "Waterworld" finally came out, its underwhelming reception was a self-fulfilling prophecy. Costner's career as a bankable leading man has never really recovered.

In honor of the film turning 20 years old today, here are 20 facts you may not know about "Waterworld."

1. Initially, "Waterworld" was to have been the opposite of a big-budget blockbuster. Peter Rader's original "Waterworld" script, written in the late 1980s, was commissioned by Roger Corman, the legendary B-movie producer of classic sci-fi/exploitation drive-in movies (and more recently, SyFy channel monster mash-up movies). But the company ultimately decided it couldn't make the film for under $3 million, so it sold Rader's script.

2. By the time it landed at Universal as a Kevin Costner vehicle, it was budgeted at $65 million, a figure that would grow to $100 million before cameras rolled -- and $172 million by the time of "Waterworld"'s premiere.

3.David Twohy ("The Fugitive") was hired to polish Rader's script. Before the film's release, some 36 writers would tinker with it, though only Rader and Twohy received credit.

4. One of those uncredited script doctors was Joss Whedon. "The Avengers" filmmaker said he was essentially tasked with putting Costner's own ideas into the screenplay. He called himself "the world's highest-paid stenographer" and called the experience "seven weeks in hell."
5. If "Waterworld" reminds you a lot of the "Mad Max" movies, that's not a coincidence. Both of "Waterworld's" credited screenwriters have acknowledged their story's debt to those two films. And Dean Semler, the cinematographer who shot them both, also shot "Waterworld."

5. For action that occurred on the surface of the water, celebrated surfer Laird Hamilton was Kevin Costner's stunt double.

6. Yes, that's a very young Jack Black in a small role as a pilot. "Waterworld" was only his fifth movie.

7. Most of the movie was shot on the ocean, off the coast of Hawaii. You'd think Universal would have known better, given the hurricane-plagued shoot they suffered there two years earlier, with "Jurassic Park." Indeed, a hurricane hit the "Waterworld" set, too. The storm sank the floating Atoll set, which then had to be rebuilt.
8. Early in the shoot, co-stars Jeanne Tripplehorn and Tina Majorino (pictured with Costner) were thrown from The Mariner's boat when the bowsprit snapped off, and they nearly drowned. A team of 12 divers rescued them.

9. Norman Howell, the stunt coordinator for the underwater scenes, came up too quickly from a dive and suffered an almost fatal case of "the bends."

10. Costner himself nearly died during a sequence when he was lashed to the mast of his boat. The craft drifted off to sea, and it took nearly half an hour for the rescue team to reach Costner and untie him.

11. "Waterworld" marked the fourth collaboration between Costner and director Reynolds (their previous collaborations were "Fandango," "Robin Hood: Prince of Thieves," and "Rapa Nui," which Costner produced but did not star in). Despite their long-standing relationship, Reynolds and Costner clashed over creative decisions. (Reynolds reportedly wanted the hero to be more stoic, while Costner wanted his character to be more swashbuckling. The performance seen in the finished film displays both traits.)

12. During post-production, less than three months before the film's release, Reynolds quit "Waterworld" (some reports had Costner firing Reynolds), and the star finished editing the movie himself.

13. Composer Mark Isham was fired for having created a stark, world music-y score that didn't seem to fit the tone that Costner wanted. At the last minute, James Newton Howard (who had scored Costner's "Wyatt Earp") came aboard and whipped up a traditional orchestral score.
14. All the turmoil had caused the shoot to balloon from a scheduled 96 days to 157 days, and the budget swelled as a result. By the time distribution and marketing costs were added, "Waterworld" had a price tag of $235 million.

15. "Waterworld" opened at No. 1 on the box office. Over the course of its theatrical run, it made back $88 million in North America and another $176 million overseas. About half that $264 million worldwide total went back into the studio's pockets. It may have taken until the Blu-ray release in 2009 for the movie to finally break even.

16. Clever accounting on the part of Universal minimized the studio's losses. The movie was in production while Matsushita sold Universal to Seagram. But Seagram made it a condition of the deal that Matsushita hold on to most of the studio's debt, including almost all of the cost of producing "Waterworld." Seagram was on the hook only for the movie's expenditures that occurred after the sale closed in the spring of 1995, which amounted to only about $12 million in post-production costs.
17. At the 1996 Golden Raspberry Awards, "Waterworld" was nominated for four Razzies, including Worst Picture, Worst Actor, and Worst Director. It lost three of the four, but it won Worst Supporting Actor for villain Dennis Hopper.

18. "Waterworld" also scored one Oscar nomination, for Best Sound Mixing.

19. Seventeen years later, Costner and Reynolds buried the hatchet and worked together again on the Emmy-winning 2012 History Channel mini-series "Hatfields & McCoys."

20. Fun fact: In June 2015, Tina Majorino tweeted that while shooting the film, she was stung by jellyfish on seven different occasions. These incidents inspired Costner to nickname her "JC," for "Jellyfish Candy."