On Sept. 23 and Sept. 24, artists from all different genres performed at the iHeart Radio Music Festival in Las Vegas. While country musicians and rockers also took the stage, pop was really the driving force behind the two-day concert experience at the MGM Grand Garden Arena. Lady Gaga, Jennifer Lopez, Jay-Z, Alicia Keys, Nicki Minaj, Coldplay, Bruno Mars, David Guetta all performed at the iHeart Radio fest, and there were even some surprise guests that took the stage with these pop stars.

As you can see in these pictures, Lady Gaga's set was the most elaborate and electrifying, with countless stage props ranging from a tricked-out motorcycle to strippers poles and illuminated signs reading 'SEX' and 'XXX.' On top of having amazing props and costumes, Lady Gaga also performed a duet with Sting, who channeled his inner little monster by smearing some fake blood on his neck Gaga style. Jay-Z also performed with Alicia Keys, treating the crowd in Las Vegas to a live rendition of their hit 'Empire State of Mind.' Nicki Minaj kept her bubble-gum Barbie theme going onstage, while David Guetta was joined by Usher for a performance of their new single 'Without You.'

Check out all of these pictures from the iHeart Radio Music Festival and let us know whose performance you would've liked to see the most.