David James, Paramount Pictures and Skydance Productions via AP

The Mission: Impossible series has been a staple of pop culture since its first iteration in the 1960s, thanks to a catchy Lalo Schiffrin theme song, one particularly memorable line (“Your mission, should you choose to accept it …”), high-tech gadgets and enjoyably convoluted plots that always keep audiences guessing.

Here are some little-known facts about the series, its history and some of the behind-the-scenes stuff that has gone into making Mission: Impossible as successful as it is. In addition to the sources noted below, this information was gleaned from the websites IMDB.com, shortlist.com and phactual.com.

Exploding fish tanks
Christof Stache, Associated Press

Cruise is more than just the star of the Mission: Impossible movies. Since the first one in 1996, he has also been a producer and even contributed creatively. One of the most iconic shots from “Mission: Impossible” — the exploding fish tanks at the restaurant in Prague — was his idea. To pull it off, Cruise had to do it without a stunt double — which would quickly become a pattern for these movies — despite a sizable risk of being drowned under the 16 tons of water contained in the tanks.

Photo: "Mission: Impossible" press conference

Tom Cruise's salary
David James, Paramount Pictures and Skydance Productions via AP

Robert Downey Jr.’s $50 million paycheck for “Iron Man 3” raised a few eyebrows. That’s not exactly chump change, but for “Mission: Impossible,” Cruise deferred his salary in favor of a juicy back-end deal — reportedly as much as 22 percent of the movie’s gross from theatrical and TV licensing — that wound up paying out to the tune of $70 million. To put things in perspective, “Mission: Impossible” only cost $80 million to make.

Photo: "Mission: Impossible – Rogue Nation"

Rewriting the ending
Keith Hamshere, Paramount

In February of this year, “Mission: Impossible — Rogue Nation” halted production to completely rewrite the ending, according to the Hollywood Reporter. This kind of thing rarely bodes well for a big studio production, but it’s not entirely new for the franchise. The first Mission: Impossible movie started filming before anything but the beginning and ending had been scripted.

Photo: "Mission: Impossible – Rogue Nation"

The rotating director’s chair
Paramount

One of the series’ hallmarks is the rotating director’s chair. Each installment has had a different filmmaker’s vision to guide it, resulting in some drastically different takes on the Mission: Impossible formula. That’s never been the plan, though. Brian De Palma was asked to return after “Mission: Impossible” but declined. Likewise, “Mission: Impossible III” director J.J. Abrams had planned to return for “Mission: Impossible IV” but had to bow out, staying on instead as a producer. His replacement, Brad Bird, who was likewise asked back for “Mission: Impossible V,” jumped ship to direct “Tomorrowland.” In other words, the only director who hasn’t been asked back so far was “Mission: Impossible II” director John Woo.

Photo: "Mission: Impossible III"

David James, Paramount Pictures and Skydance Productions via AP

For even the most computer-illiterate filmgoer these days, there is at least one glaring flaw in the 1996 “Mission: Impossible” involving what was, at the time, still pretty cutting edge for most audiences. Namely, in a key moment in the film, an email is sent to the completely impossible email address "[email protected] 3:14."

Photo: "Mission: Impossible – Rogue Nation."

Jim Phelps
Stephen Vaughan, Paramount Pictures

Jim Phelps, the traitorous IMF team leader played by Jon Voight in the first “Mission: Impossible,” was actually the main character throughout most of the original “Mission: Impossible” TV series. There had been plans to have more of the original team appear. According to series co-star Martin Landau, an early draft of the script featured all of the TV show’s IMF agents being killed off one by one. That, combined with the filmmakers’ treatment of the Phelps character, left most of the original cast less than pleased with the reboot.

Photo: "Mission: Impossible III"

Record-breaking opening
Christof Stache, Associated Press

“Mission: Impossible” was the first movie to open in more than 3,000 movie theaters nationwide. It was also the first major Hollywood production after the fall of the Soviet Union to shoot in Prague, a city which has since become one of the major filming destinations for Hollywood productions, especially those trying to capture an old-world European vibe. “Ghost Protocol” later used Prague to double for Moscow.

Photo: "Mission: Impossible" press conference

Hanging from the ceiling
Murray Close, Paramount Pictures

While filming the iconic scene where Ethan Hunt is suspended from the ceiling while trying to steal top-secret files from CIA headquarters, Cruise kept hitting his face on the floor until he MacGyver-ed a simple fix: He borrowed the change a stuntman had in his pocket, which he then put inside his shoes to help weigh his feet down.

Photo: "Mission: Impossible"

The TV show
Paramount

The TV show, which ran for seven seasons, was originally inspired by Jules Dassin’s French heist movie “Topkapi” and was conceived as more of a “Dirty Dozen”-type show. All of the characters were initially written as reformed criminals recruited for top-secret assignments, not unlike Warner Bros.’ upcoming “Suicide Squad.”

Photo: "Mission: Impossible" TV series

Star Trek ties
Zade Rosenthal, Paramount Pictures

The Mission: Impossible franchise has some odd ties to another ’60s TV-series-turned-movie franchise: Star Trek. For starters, both series began in 1966. Landau, who played the “man of a million faces,” Rollin Hand, was actually Gene Roddenberry’s first choice for the Starship Enterprise’s half-Vulcan science officer Spock. After Landau left the series, his character was replaced by “The Great Paris,” a magician/master of disguise played by none other than Leonard Nimoy. “Mission: Impossible III” also served as the feature directorial debut of Abrams, who went on to helm 2009’s “Star Trek” and its sequel “Star Trek Into Darkness.” Meanwhile, series veteran Simon Pegg, who has played IMF agent Benji Dunn in the last three movies, is currently writing the as-yet-untitled third Star Trek film.

Photo: "Star Trek Into Darkness"

'Gellerese'
Bob Galbraith, Associated Press

The Mission: Impossible TV series invented its own language, nicknamed "Gellerese" after the show’s creator, Bruce Geller. Gellerese was intended to be easily intelligible to English-speaking audiences but look distinctly German or Polish. Examples include words such as “machina werke,” (“machine repair),“morturari” (mortuary), “gäz” (gas), “emerenciskija” (“emergency”) or the phrase “mina din steppen” (“mind the step”).

Photo: Cast of 1988 "Mission: Impossible" TV reboot

X-men ties
Kerry Hayes, Twentieth Century Fox

“Mission: Impossible II” baddie Dougray Scott was originally cast as Wolverine in Bryan Singer’s “X-Men” but had to drop out when filming on “Mission: Impossible II” went over schedule. Another actor from the X-Men movies, however, dodged a bullet: Ian McKellen turned down a role in Woo’s action-heavy sequel because they wouldn’t let him read the whole script. The very next day, he said in an interview with People, he got calls from Bryan Singer about “X-Men” and Peter Jackson about “The Lord of the Rings.” If he had said yes to “Mission: Impossible II,” he may not have been able to be in either of those series, and the world might have had to settle for his “X-Men” co-star and close friend Patrick Stewart in the role of Gandalf and his “Lord of the Rings” co-star Christopher Lee in the role of Magneto — both possibilities that were considered.

Photo: "X-Men: The Final Stand"

7 vs. 107
Hermann J. Knippertz, Associated Press

The 1996 “Mission: Impossible” is a mostly bloodless affair: It doesn’t feature any shootouts or gunfights. In fact, Ethan Hunt never even fires a weapon in the entire movie, and the final body count, seven, is almost entirely from the opening sequence. Compare that with its trigger-happy sequel “Mission: Impossible II,” which has 107 onscreen casualties (68 of them in a plane crash), according to a website called allouttabubblegum.com.

Photo: "Mission: Impossible II" screening

Utah ties
Ray Boren

The rock climbing sequence from “Mission: Impossible II” was filmed at Dead Horse Point in Utah.

Photo: Dead Horse Point

(Not) passing the torch
David James, Paramount

2011’s “Mission: Impossible — Ghost Protocol” was initially meant to be a passing of the torch from Cruise’s Ethan Hunt to Jeremy Renner’s William Brandt. The success of “Ghost Protocol,” however, proved that Cruise’s leading-man status was still intact, resulting in Hunt leading the IMF at least one more time for “Rogue Nation” with Renner’s Brandt again playing a supporting role.

Photo: "Mission: Impossible – Ghost Protocol"

The almost directors
David James, Paramount

The list of directors that almost helmed Mission: Impossible movies is just as impressive as the ones who actually did. Oliver Stone was originally attached to “Mission: Impossible II” but had to drop out. David Fincher, Joe Carnahan and Ang Lee were all attached to “Mission: Impossible III” at various points, while Phil Alden Robinson (“Sneakers,” “The Sum of All Fears”) was also considered. And Ruben Fleischer and Edgar Wright were looked at for “Ghost Protocol.”

Photo: "Mission: Impossible – Ghost Protocol"

Brad Bird
Joe Lederer, Paramount

“Ghost Protocol” marked the live-action directorial debut of Brad Bird, a key member of the Pixar brain trust. Pixar’s trademark “A113” — the room number for the character animation class at CalArts that Bird and many of the other Pixar animators attended — which appears in every Pixar movie to date (with the possible exception of “Monsters, Inc.”), also appears on Trevor Hanaway’s (Josh Holloway) ring at the beginning of “Ghost Protocol.”

Photo: "Mission: Impossible – Ghost Protocol"

'The Syndicate'
Chiabella James, Paramount

The shadowy organization known as “the Syndicate” in “Rogue Nation” was the name of the IMF’s frequent antagonists from the original TV show — basically the Mission: Impossible universe’s equivalent of SPECTRE from the James Bond movies.

Photo: "Mission: Impossible – Rogue Nation."

Over-the-top stunts
Christian Black, Paramount

Cruise’s over-the-top stunts, often done without computer graphics or stunt doubles, have become one of the signature elements of the Mission: Impossible movies. For “Rogue Nation,” Cruise was tethered to the outside of a flying Airbus A400M that reached altitudes of 5,000 feet. In order for him to be able to keep his eyes open against the hard air and any possible debris, Cruise had special contact lenses designed that covered his entire eye. For “Mission: Impossible II,” he performed another stunt that could have seriously damaged his vision if it had gone wrong: In a knife fight with Scott’s Sean Ambrose, an IMF agent gone bad, Cruise insisted on a shot where a real knife stops exactly a quarter of an inch from his eyeball. Cruise asked Scott to use as much force as possible to make it look real. The only thing stopping the knife was a carefully measured cable attached to its handle.

Photo: "Mission: Impossible – Rogue Nation."