From 'Harlem' (Shake) To (Bruno) Mars, 2013 Hasn't Been Half-Bad

Bruno Mars performs onstage at the 2013 Billboard Music Awards in Las Vegas.

As we begin the second half of 2013, a look back at some of the most notable chart feats from January through June

You've already weighed in on your favorites of the first six months of 2013 in's mid-year awards poll. Let's see how your picks matched up with the songs and artists that made that the biggest chart headlines – 26 below, for the year's first 26 weeks – from January through June.

Jan. 19
"Les Miserables: Highlights From the Motion Picture Soundtrack" jumps 2-1 on the Billboard 200. Meanwhile, a venerable composition from the musical enters the Billboard Hot 100, as Samantha Barks' "On My Own" debuts at No. 97. Although "Les Miserables" has been a hit stage musical worldwide since the '80s, Barks, who plays Eponine in the film adaptation, brings the ballad to the Hot 100 for the first time.

Jan. 26
Billboard debuts the Dance/Electronic Songs chart, the first tally incorporating airplay, sales and streaming for the genre. and Britney Spears score the first No. 1 with "Scream & Shout."

Jan. 26
Banjos on top 40 radio? Yup. Reinforcing pop radio's folk invasion (the Lumineers, Ed Sheeran), Mumford & Sons' "I Will Wait" enters Pop Songs at No. 36, marking the band's first entry on the airplay chart. "Wait" previously topped Triple A and Alternative Songs. "The best-testing songs are the ones we should play most often," Dave Adams, program director of Pop Songs panelist WRNW Milwaukee, advises.

Feb. 2
51-year-old Wanz tops the Hot 100 as the featured artist on Macklemore & Ryan Lewis' "Thrift Shop," which crowns the chart with a 2-1 advance. "At 51 years old, what are the odds that this will ever happen again? Pretty slim," he told Billboard. (Louis Armstrong holds the record as the oldest artist to crown the Hot 100. The late jazz legend was 62 years and nine months old when his "Hello, Dolly!" topped the May 9, 1964, chart.)

Feb. 16
Justin Bieber achieves his fifth No. 1 album on the Billboard 200 as "Believe Acoustic" debuts atop the list. With the arrival, he becomes the only artist to have notched five No. 1 sets before age 19. He was previously tied with Miley Cyrus, who had also posted four leaders before her 19th birthday.

Feb. 23
With a 19th week atop Alternative Songs, Muse's "Madness" rewrites the record for the longest stay at No. 1 in the survey's 24-year history. The track bests the 18-week domination of Foo Fighters' "The Pretender" in 2007. Muse also boasts the next title on the list of those with the most weeks atop Alternative: the trio spent 17 weeks at No. 1 with "Uprising" in 2009-10.

March 2
The Hot 100 undergoes a major shakeup, as YouTube streaming data joins the chart's methodology. Fittingly, "Harlem Shake," the viral smash from Brooklyn producer Baauer, roars onto the ranking at No. 1. "Shake" becomes just the 21st song in the chart's archives to debut at the summit. "When something like 'Harlem Shake' happens, you can't ignore it," Chris Patyk, program director of CBS Radio pop station KEGY San Diego, said. "It feels like a novelty song with a short lifespan, but right now is the time to play it."

March 16
Bruno Mars claims his first No. 1 album on the Billboard 200, as "Unorthodox Jukebox" jumps 2-1 in its 12th week. The set reigns fueled largely by Amazon MP3 sale-pricing, as on Feb. 26, the digital retailer offered a host of albums, including "Jukebox," for just $1.99.

March 16
Bruno Mars wasn't the only beneficiary of Amazon MP3's one-day sale. Billboard was, too! "Joel Whitburn Presents: Billboard #1s: The '70s" roars onto the Billboard 200 at No. 11 following the discounting, marking a Billboard-branded set's highest perch in the chart's 57-year history.

April 6
Justin Timberlake's third solo album, "The 20/20 Experience," debuts at No. 1 on the Billboard 200. Another way to frame his success? Having led twice solo and as a member of 'N Sync, he's just the seventh artist in the Billboard 200's history to notch multiple No. 1 albums both with a group and as a soloist. He joined Beatles Paul McCartney, John Lennon and George Harrison, as well as Eric Clapton, Eminem and Beyonce.

April 13
Darius Rucker rolls "Wagon Wheel" to No. 1 on Hot Country Songs, granting Bob Dylan his latest chart leader, as well. Dylan is credited as a co-writer of the song, as Old Crow Medicine Show's Ketch Secor reworked it from a Dylan bootleg, commonly referred to as "Rock Me Mama." Dylan logs his first Hot Country Songs No. 1 as a writer since 1998, when Garth Brooks' cover of his 1997 composition "To Make You Feel My Love" reigned for a frame.

April 20
Amid a boom of hi-NRG EDM club anthems, stomp-and-clap folk/rock sing-alongs and rap, a simple piano ballad, Bruno Mars' "When I Was Your Man," crowns the Hot 100, reinforcing Mars' star status. The song sports only Mars' vocals and his own piano accompaniment. Only one other No. 1 also features nothing but vocals and piano: Adele's "Someone Like You," which ruled for five weeks in 2011.

April 27
As she crowns the Hot 100 with "Just Give Me a Reason," with fun.'s Nate Ruess, P!nk concurrently collects her first Adult Contemporary No. 1 with prior single "Try." "P!nk has proven that her appeal is not relegated to any one format, genre or demo," noted Adrian Moreira, RCA senior VP of promotion. "I think that her topping AC is a testament to the fact that her songs resonate among a wide swath of fans." Meanwhile, upon learning of her new honor, Pink Tweeted, "Ha!!!!! Mama just got a Billboard Hot 100 #1!!!!!!!!!!!! What!?!?!"

NEXT: May-June

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