We knew Trey Parker and Matt Stone were hilarious back in '97. In 1999, we learned they were musical geniuses, as well.

At this point, Trey Parker and Matt Stone's impressive musical chops are a matter of public record. Team America: World Police - the pair's 2004 takedown of Michael Bay movies, Broadway and Bush-era politics - featured a number of songs that have become pop-cultural touchstones ("Freedom Isn't Free," "America: Fuck Yeah," "I'm So Ronery"), and their hit Broadway show The Book Of Mormon won nine Tony Awards following its 2011 debut, including that year's award for "Best Musical." The duo's long-running Comedy Central series, South Park, has also featured a parade of memorable musical moments (this season's "I Am Lorde (Yeah Yeah Yeah)" seems to have proven particularly popular, but let's not forget "Gay Fish," "There Are Too Many Minorities (In My Waterpark)," the anime-flavored "Let's Fighting Love" and, of course, the immortal "Chocolate Salty Balls"). But way back in 1999, most of us were unaware of Stone and Parker's musical talents (if we'd seen Cannibal! The Musical, we'd have seen it coming...but at that point most of us had no idea the film even existed).

We were aware, however, that Stone and Parker were tremendously funny, because everyone and their mother seemed to be watching the team's insta-hit Comedy Central series, South Park. Much like The Simpsons before it, the show was a flat-out culture bomb when it debuted in 1997, embraced by naughty kids, surly teens and the sort of enlightened adults who could appreciate an off-color joke or ten. And just like The Simpsons, South Park's debut was greeted with no small amount of controversy: schools banned t-shirts emblazoned with the show's lead characters, parents went off the deep end decrying the show's sophomoric humor, editorials were written wondering if the show's popularity didn't signal the end of culture as we know it. It was a magical time, and it only served to build hype for the arrival of the South Park movie in 1999.

I don't recall being aware that South Park: Bigger, Longer, And Uncut was a musical before seeing the film. I do recall the opening night screening I attended, though: to this day, I have never heard a theater full of people laughing as hard at a film as they did during the South Park movie. This was deep, hysterical laughter, people gasping for breath and crying from the force of it. That movie landed like a bomb on the theater I was in, and, based on conversations I've had with others in the time since, I don't think that was an anomaly. South Park: Bigger, Longer, And Uncut (even the title is hilarious*) is a riotously funny movie from start to finish, offering up a perfectly-blended combination of themes that would go on to become hallmarks of Stone and Parker's work in the years that followed: a deeply-ingrained disgust with censorship, disdain for our country's often-hysterical media and savage mockery for any authority figure who's ever revealed themselves lacking in accountability, from clueless parents all the way up through the highest peaks of our government. And of course, there were the songs.

The throughline for South Park: Bigger, Longer, And Uncut is strong, but these days it's the music that keeps me coming back. The film kicks off with Stan performing "Quiet Mountain Town," a terrific opening number that starts off tranquil and cute - whimsical, even - before snowballing along to reveal that Stan's "quiet mountain town" is filled with grumpy weirdos, alcoholic deadbeats and religious fanatics (all while setting up the film's inciting incident: Kyle, Stan, Kenny and Cartman attending an opening-day screening of "a foreign film, from Canada" called Asses Of Fire). It's a delightful little song that perfectly sets the tone for everything that's to come.

This leads to "Uncle Fucker," which, for my money, is the South Park movie's greatest musical achievement. It is a genuine showstopper. Pay attention to the sequence's escalating sense of scale: in the tradition of any number of classic musicals, things start simply, with Terrence and Phillip sitting on their couch, and then the action just keeps ratcheting up until the pair have dragged what appears to be an entire city block into a full-on celebration of mind-bogglingly inventive profanity that retains its punch even now, a decade and a half later ("Shut the fuck up, you donkey-raping shit-eater"). Asses of Fire is basically a stand-in for the foul-mouthed cartoon parents, teachers and pearl-clutching conservatives suspected South Park to be, adding another level of funny to a spectacle that's already way more clever than it has any right to be.

The damage wrought by Asses Of Fire leads to a scene where South Park's resident guidance counselor, Mr. Mackey, attempts to de-program the now compulsively-swearing kids by performing a song called "It's Easy, Mmmkay." Of course, this is presented with a typical South Park twist: even the song decrying profanity is packed with naughty words ("No, you shouldn't say 'fuck'/No, you shouldn't say 'fuck'/fuck, no"), and immediately after claiming they've been reformed we see the kids back in the theater, watching Asses Of Fire a second time. The message, of course, being that kids are going to swear no matter what adults say, not because they're headed towards self-destruction, but because when you're a kid swearing is fun and cool (this concept that would've been completely lost on South Park's most vocal critics).

Of course, the angry parents of South Park are desperate to find someone to blame for their potty-mouthed kids, leading to the film's most well-known number, "Blame Canada." The song went on to be nominated for a "Best Original Song" Oscar at the 2000 Academy Awards, where it was performed by the late Robin Williams. If you've somehow managed to avoid seeing that performance, here it is, in all its glory**:

Another highlight: when Kenny is inevitably killed and sent to Hell, we're treated to "Hell Isn't Good," which features cameo appearances from Hitler, Mahatma Gandhi and, inexplicably, George Burns. Another cameo worth noting? Metallica's James Hetfield, who sings lead vocals on the track (this was denied at the time, but Hetfield apparently confirmed this to be the case in an interview several years later):

Once in Hell, Kenny encounters Satan, who's trapped in an abusive relationship with Saddam Hussein. Saddam is using Satan to return to Earth, where he hopes to facilitate the apocalypse and rule over whatever remains of mankind. Satan, meanwhile, turns out to be a bit of a gentle giant who longs to cavort on luxury yachts with well-oiled cabana boys under clear, blue skies. "Up There" - a direct send-up of The Little Mermaid's "Part Of Your World" - must be seen to be believed. And even if you have seen it, watch it again: it never gets old.

Eventually, all hell breaks loose: when the United States announces their plans to execute Terrence and Phillip for corrupting the nation's youth, Canada vows to launch an all-out attack on the country. This is, of course, all a part of Saddam Hussein's evil plan, and...look, it's complicated (hilariously so). The point I'm getting to is, the action builds up to a brilliant, overlapping reprise of a number of the film's best musical numbers: combining the Disney-fied "Up There" with the Les Miz-flavored "La Resistance," the sweetness of "Quiet Mountain Town," the bombast of "Blame Canada" and a perfectly-executed callback to "Uncle Fucker," "Execution Night" is straight-up masterful:

It's been a long time since anyone was foolish enough to wave Trey Parker and Matt Stone off as crude amateurs horning in on the territory established by The Simpsons (that honor now belongs to the stupefyingly unfunny Family Guy); they have long-since acquitted themselves as the reigning satirists of my generation. But it's important to remember how caught off guard we all were when South Park: Bigger, Longer, And Uncut hit theaters (even the fans seemed stunned at the level of quality the film delivered), and I feel like a huge chunk of that surprise is owed to the musical talent Stone and Parker showcased in the film. In 1997, who would have predicted that these two might write and direct the best musical comedy of the '90s?  Hell, one of the best musical comedies ever made?

Because Stone and Parker consistently aim high, each feature film project they've taken on has turned out to be incredibly difficult (they fought with Paramount over the content of the South Park movie, and they wrestled with the physical challenge of directing puppets in Team America right up until that film's pre-announced release date); as a result, Stone and Parker always seem reluctant to get back behind the camera after each feature they mount. But it's impossible to watch the South Park movie now and not come away wishing that they didn't have more of a presence in movie theaters. Here's hoping they'll eventually bring The Book of Mormon to the big screen***, and that when they do it blows the doors off theaters in the same way that South Park: Bigger, Longer, And Uncut did all the way back in 1999.

* = And doubly so when you realize that it was actually Stone and Parker's second choice: the MPAA found their original title, South Park: All Hell Breaks Loose, to be offensive, while the double-meaning of the alternately suggested title sailed right over their heads. Clowns.

** = This is the same Oscar ceremony that Parker and Stone famously attended while dressed in revealing ballgowns. A lesser-known fact is that they were also on acid at the time. Consider being Trey Parker and Matt Stone, sitting inside the Kodak Theater with a head full of acid, watching Robin Williams perform a song - with backup dancers! - that they co-wrote for the South Park movie. Just marinate on what that must've been like for a bit. The mind reels.

*** = Shameful admission: I have not seen The Book Of Mormon yet.