Adele's second studio album 21 explores themes of heartbreak through soul music. Released in 2011, the album topped charts in over 30 countries and had three worldwide number-one singles. The album packaging utilizes conventions of the soul music genre like monochrome colors and close-ups of Adele's expressive face, while also including elements of pop music like a bright green color on the CD. These conventions are consistently represented across the vinyl, CD, and digital packaging to clearly identify the artist and emotion of the music.