Stream Katy Perry's 'Witness' Album Now

Katy Perry's first album in nearly four years, Witness, has arrived. Featuring Nicki Minaj, Migos and Skip Marley (on the lead-up singles "Swish Swish," "Bon Appétit" and "Chained to the Rhythm"), the record runs 15 tracks and just under an hour. It follows 2013's Prism, which included "Roar" and "Dark Horse."