You could definitely say that there are fads in pop music. In fact, following certain trends in sound and fashion can make or break whether someone is even considered a "pop artist." One of our favorites of these particular fads is when artists have one of their albums follow a circus theme. The animals, the feathered hats, the bedazzled straps and costumes, the showmanship aspect of it all -- maybe it's something that just works in music, or maybe these few great pop minds think alike.

Not sure what show the Ringling Bros. and Barnum & Bailey Circus was doing in 2008, but maybe it's just a coincidence that four out of the six albums on our list were released in the fall of that year. All the same, we know that we love seeing P!nk twirl around in the air on an aerial ring and Britney Spears pull doves out of a top hat. With Ringling Bros. back at NRG Stadium through Sunday, here's our list of the six best circus-themed albums.

6. T-Pain Thr33 Ringz (2008)

When you think of T-Pain, you may initially want to brush off the rapper as a bit of a joke -- some kind of outlandish Lil Jon/Flava Flav-esque hip-hop spectacle. True, it's pretty valid to think that -- a good portion of the rapper's success is arguably indebted to his use of Autotune, which shook up the popular-music scene in the late 2000s and even got us all imitating him with our friends on the "I Am T-Pain" iPhone app.

However, beneath the infamous dreads, heavy chains and bold top hats, it's not crazy to think that there is a bit of genius there. His third album, Thr33 Ringz, follows the theme of a three-ring circus and takes a small step back from "Buy U A Drank" and the other big club bangers characteristic of his previous work.

Although this record wavers between raw and deeply emotional ("Keep Going") and ridiculously humorous ("Long Lap Dance"), the central theme of Thr33 Ringz is summed up in these lyrics: "This is my circus I'm working/ I can flip this whole game with one hand." T-Pain is confident in his abilities and establishes himself as the ringleader of his very own mini-rap revolution.

5. Take That The Circus (2008)

Because of its completely insane accompanying tour, Take That's The Circus, the band's second album since their 2005 comeback, ranks among the most devoted circus-themed albums. Lead single "The Greatest Day" was huge overseas and peaked at No. 1 in the UK, while the album itself became the most pre-ordered album of all time and had the third-highest opening sales week in UK history. Critics praised the album, the majority agreeing that it had some of the most well-crafted pop music and most top-notch production of 2008. But that stadium tour...

"Take That Presents: The Circus Live" featured a huge, overwhelmingly dazzling stage and screen, loads of fire, hundreds of clowns and props, balloons galore, white doves and an enormous metal elephant, atop which the band performed. And they didn't just let the other performers do all the work.

Take That performed their sets decked out in full circus costumes, and even took some time to perform their very own tricks. Most shows were performed in stadiums with capacities of 40,000-plus, but concertgoers must have felt like they were right there under that red and white circus tent, experiencing the real thing.

4. Christina Aguilera Back to Basics (2006)

Christina Aguilera took on a lot of different roles from the 1920s, '30s, and '40s on her career-defining Back to Basics album. There was the old-fashioned burlesque performer in "Ain't No Other Man," the glamorous World War II pinup in "Candyman," and even Aguilera's newly-adopted alter ego named Baby Jane, an ode to classic Hollywood movie stars to whom she credited her freshly adapted public appearance.

But perhaps the best came in songs like album standout "Hurt" and "Enter the Circus." For this part of the album, the music seems way more heartfelt and dramatic, with eerie circus music surrounding these songs in an extremely haunting aura of nostalgia.

A hugely successful and equally retro world tour followed, eventually becoming the ninth highest-grossing tour ever for a female artist. Overall, Back to Basics completely broke all of the remaining chains that were still tying Christina to the bubblegum pop-star image she emerged with. Come on, who can ever forget that platinum blonde hair?

3. Britney Spears Circus (2008)

After her 2007 breakdown, Britney Spears needed a solid, commercially successful album to bring her back to the surface of pop music, and Circus delivered. Featuring a newly improved, more put-together Britney, the album produced two megahits, "Womanizer" and "Circus," right off the bat proving that the pop princess had still got it. They say that you make your best work when you're crazy, and many critics stuck to that statement.

Britney's previous album, Blackout, had been released during the time of her highly publicized personal struggles; surprisingly, it drew more favorable reviews than Circus, critics saying that its experimental beats and risk-taking sound set a new bar for modern pop music. However, Circus came down squarely on the side of the general public.

"Womanizer" became Britney's best-selling song since "...Baby One More Time," and the album managed to sell more than half a million copies in its first week. The tour, "The Circus Starring Britney Spears," soon followed, with her manager calling it "a full-blown, full-out Britney Spears show. It is everything everybody expects from her and more." The four-leg tour lived up to it, extending the album's circus visuals into a live setting with flashy costumes and props and a three-ring stage designed to resemble an actual circus. Everything we expect from Britney Spears, indeed.

List continues on the next page.