Capital's Summertime Ball 2015 is nearly over but first Avicii treats us to a mind-blowing set! This image appears in the gallery:One Direction, Ariana, Avicii & More! The MUST-SEE Pictures From Capital's Summertime Ball 2015 165. Capital's Summertime Ball 2015 is nearly over but first Avicii treats us to a mind-blowing set! Picture: Danny North 171 images See the full gallery: One Direction, Ariana, Avicii & More! The MUST-SEE Pictures From Capital's Summertime Ball 2015