Prior to 2016, the last song by a girl group to climb into the Top 10 on the Billboard Hot 100 was The Pussycat Dolls' "When I Grow Up" in July of 2008. That's over eight years ago, before the general public even heard of Lady Gaga...or Twitter. (Cue millennial gasp.)

While superstar troupes like Girls' Generation, 2NE1, Little Mix and Girls Aloud have thrived on the international charts in recent years, American girl groups have been few and far between — but Fifth Harmony is intent on putting an end to the drought.

As overdramatic as it sounds, Fifth Harmony represent hope for the new generation of girl groups in America: they're the only US girl group out here really doin' it. Their existence is important, and they're steadily improving.

7/27, the group's follow-up to their 2015 debut released today (May 27), finds Fifth Harmony successfully digging their stilettos deeper into a pop landscape that has been awfully unfriendly to their kind in the past decade.

Moving away from their scattered, occasionally embarrassing Reflection (how unfortunate that they'll always have "Them Girls Be Like" in their discography), 5H's second go-round feels more confident and fresh — and much better suited to the girls' personal taste.

Unlike the endless start-and-stop campaign leading up to the release of Reflection, "Work From Home" perfectly set the tone for 7/27.

Armed with power drills, sledgehammers (reference!) and measuring tape, the ladies upped the flirt factor tenfold alongside sweat-drenched construction workers, serving above-average choreography that, in an age when hardly anyone's dancing, felt like a small victory for those of us thirsting for a provocative bend, snap and a hair flip.

The song itself is a subtle smash, with its minimal, Rugrats theme-sounding beat, finger snaps and inescapable drone of a chorus. "Work, work, work, work": a proven lyrical formula for success time and time again...just ask RiRi.

The girls legitimately just wanna have fun on the largely celebratory 7/27, as evidenced by "The Life," a #turnt-up Tinashe co-penned anthem devoted to getting lit AF and drinking Mai Tais poolside. (Never mind that most of them aren't even 21 years old yet.) It's frivolous, fleeting fun. What else should a group of teens on top of the world be doing right now?

Like "Worth It" and "Bo$$," Fifth Harmony are at their best when they're providing a boost of self-empowerment, Girl Power 2K16 style.

"Not That Kinda Girl," a bouncy, retro electro ode to boundary-drawing and sass-talking, smacks of classic Prince in one of the album's greatest highlights. Missy Elliott is a welcome addition, as she fires off further dismissals alongside the girls. And yes, there is a very real joy that comes from hearing them all sing "Don't get it f--ked up / I'm not that kinda girl." Very here for F--k Harmony.

Even better — or at least more instantly begging to be the next single — is the anthemic opener, "That's My Girl." Backed by a funky horn stomp, the track feels like the natural continuation of "Worth It." But this one goes much bigger, armed with a nasty spitfire pre-chorus ("Destiny said it, you gotta get up and get it / Get mad independent and don't you ever forget it") and a fist-raising, flag-waving chorus that would make The Saturdays proud.

That said, the girls haven't quite carved out a signature 5H sound just yet, and dip perhaps too heavily into radio trends: The reggaeton-inflected "Flex" is essentially a Mad Cobra karaoke session — dancehall's all the rage right now, didn't you know? — featuring last year's flavor of the moment, Fetty Wap.

The lyrically confounding "Write On Me," one of two songs co-produced by Kygo, hops aboard the "trop-House" movement du jour. And what it lacks in sense (at one point, it seriously sounds like Camila is singing "everything is bacon 'til you draw me"), it makes up for in pleasant vibez. (And harmonies!)

Beyond the partying, flexing and construction working, the girls go for deeper feelings at the tail-end of 7/27: The StarGate-produced "Scared Of Happy" is a skittering ode to insecurity, while "Dope," a spacey, electro-R&B swoon-fest for the speechless is unlike anything they've ever done. ("I don't know what else to say, but you're pretty f--kin' dope.") Have I mentioned how much I love Swear Harmony?

While "No Way" may not be the most uplifting song to end the LP, it's possibly the most impressive, as the girls grapple with a complicated relationship amid unwanted opinions from outsiders. It's a grown ballad, vaguely reminiscent of Jhene Aiko or perhaps a 5H take on an ANTI track. (Surely, it's one of Lauren's favorites.) It's also the kind of song that suggests we're still only just at surface level with 5H — there's still so much further they can go.

There's a scrappy quality to Fifth Harmony that makes the group such endearing underdogs. They show up to most red carpets looking like they're each separately dressed for a wedding, a funeral and a prom. (Just look at that album cover.) Camila goes overboard on her ad-libbing during almost all live performances. Normani out-dances them all. They are far from a perfectly polished, synchronized unit, at least for now — and it somehow (mostly) works.

The threat of any one Harmony pulling a Halliwell (or, for this generation, a Malik) and jumping ship while the group is still work, work, working still looms heavily over the group's heads, spurred on by both neurotic fans and the media picking apart their every answer in an interview, solo endeavor and social media post.

But they've already proven the skeptics wrong twice, and by the sound of it, they've got at least several more potential smashes-in-waiting lined up on their step-up of a sophomore record. (Here's hoping, anyway.)

"We got an audience calling us crazy / We ignore opinions of hate," the girls sing on "No Way." Ostensibly, it's about a questionable romance. But really, it feels more like a vow between the girls themselves. They're better together, after all.

20 Photos of Fifth Harmony, from X Factor USA to Today