When it comes to Britney Spears tours, picking a favorite moment can seem impossible. After all, the 34-year-old has been hitting the road since 1999, when she was still a teen. There was the Dream Within a Dream of whiplash dance moves through a stormy jungle, seductive serenades at the Onyx Hotel, and the titillating Freakshow Peepshow when the Circus came to town in 2009, just to name a few.

But since Brit's Piece of Me residency is once again in full Vegas momentum, what better way to pay respect to the tours that brought her Sin City masterpiece into full bloom? Taking humbled prayer photos while kneeling before the pop princess's Planet Hollywood elevators is certainly one approach, but I decided revisiting these six historic shows -- from good to greatest -- was long overdue. So let's check in!

The ... Baby One More Time Tour (1999)

This last-place rank is entirely situational. It was Brit's shortest major tour, had the smallest hit list, and an extremely minimal stage design that reflected the early phase in her career. Not that the pop princess needs more than a staircase and a "Stronger"-esque chair to slay. But the impact is there: The spunky choreography, background dancers, and vocal playback on the ... Baby One More Time tour became a totem for most Britney shows to this day.

And don't undersell the work put into this small-scale debut. "They had a little say-so, but I had the main say-so," Britney told CNN in 1999 of taking the creative reins in collaboration with fashion designer Gia Ventola. Fans loved it, but Nestlé pulled its tour sponsorship after seeing her sexy David LaChapelle photo shoot for Rolling Stone.

When will your teenage fave?

The Femme Fatale Tour (2011)

The mere mention of the Femme Fatale tour can bring out the worst in fans. Actually, many argue it brought out the worst in Britney. Reportedly, the singer wasn't on board with the creative direction on her seventh studio album — led by producer Dr. Luke and onetime label Jive Records — and it showed in her low-energy performances and limited audience interaction on the tour for it.

This was (somewhat) balanced out by a solid set list and a thrilling story line starring Brit as a secret agent being stalked by the fictional Tormento Lancie.

The Oops! ... I Did It Again Tour (2000-2001)

The ... Baby One More Time saga was merely a warm-up to the Oops! tour, which was lit. The show grossed over $40 million — an impressive feat for a second tour promoting a sophomore album. Instead of a clear story line, Brit went for a Broadway-inspired musical medley of her more popular tracks. So if you're looking for an explanation for the sailor outfits and giant metal orbs, please consult the Manhattan prop closet Britney's team raided for the show.

A particularly unique aspect of the tour was that it featured mostly live vocals from Brit and a live band. That may have been a clapback at Britney critics who questioned the pop princess's ability to juggle vocals with choreography.

Her critics found other things to criticize, though, as they would over the course of her career: The tour was simultaneously called out for being too immature — frankly ridiculous considering the star was a teenager — and too mature.

The Circus Starring Britney Spears Tour (2009)

Brit hired director Jamie King for her '09 show. What was really brilliant about Spears and King is that they avoided many of the obvious circus clichés — lions, tigers, and elephants (oh my!) — giving Brit and company a stage design that wouldn't distract from the choreographed performance elements. The set list also acknowledged the missing Blackout-era tour by featuring just three tracks from the Circus album and six from 2007's Blackout.

It was during this tour that manager Adam Leber and the Britney Army famously dragged an Australian journalist for supporting the audience outrage over Britney's lip-synching and "crap" dancing in Perth. (Suggestion: If you're shocked to discover lip-synching on a Britney Spears tour, you might want to reconsider your status as a fan ... or a casual observer of pop music in general.)

The Dream Within a Dream Tour (2001-2002)

"I was going through a run-through yesterday and was thinking, ‘By the time I’m 30, there’s not going to be anything left for me to do,'" then-20-year-old Britney told her audience at the November 2001 kick-off show of the Dream Within a Dream Tour.

Just look at our gal now. I might shed a tear.

Directed and choreographed by Wade Robson, the look of the tour captured the fantasy implied by its title: everything from ballerina-Britney music boxes to 18th-century-inspired outfits to jungle landscapes. Remarkably, the theatrical elements didn't overshadow that this show was also about Britney's coming of age. Robson's greatest tour hit was probably the signature finale though. Picture a circular screen (basically a giant shower head) with 360 gallons of water pouring out of it each minute, drenching the stage but not Britney and her dancers until the right moment. The technical team had to work to make sure the water effects didn't damage the electrical equipment. It's no wonder the show, which was broadcast on HBO, earned an Emmy for Outstanding Technical Direction in 2002.

The Onyx Hotel Tour (2004-2005)

To this day, the Onyx tour is widely recognized as the pop princess's most successfully executed stage venture. And unlike the majority of Britney's tours, The Onyx Hotel was modeled after one specific musical, Grand Hotel, instead of a general Broadway theme. From Check-In to the Mystic Lounge to the jazzy musical interpretations, the tour recreated early 1930s New York with a modern twist. Britney's nonstop travel schedule also inspired the theme, giving the production a hint of personal flavor, too.

By this time, Britney was practically synonymous with MTV, so it's no shock that the network decided to sponsor this (flawless) tour. MTV even devoted three episodes of TRL to the show, showcasing behind-the-scenes footage for fans.

So what exactly was the Onyx Hotel? According to an old post on Britney's website, it was "a vibrant, whimsical place where wondrous dreams are realized, and the darkest of secrets are revealed."

Blessed is anyone who ever had the chance to check in.

Note: The M+M tour is not included in this list, as it was a small promotional tour. Similarly, the C2K tour is not included as it was essentially a short continuation of the ... Baby One More Time Tour.