Revellers get to relax inside a 3D luminarium inflatable installation - a maze of tunnels, domes and pods - by British designer Alan Parkinson during the Sziget music festival.

The week-long festival, which is held annually in August, takes place on an island in the Danube River in Budapest, Hungary. It is one of Europe's largest outdoor music bonanzas. It kicked off on Monday evening, featuring more than 500 concerts by top international acts.

Last year's edition drew a record 415,000 visitors from 87 countries.

British pop boasts a stellar presence in this year's edition, with big names like Alt-J, Florence and the Machine, Ellie Goulding, Foals, and Kasabian, as well as Robbie Williams, the opening act.

Other big acts that are set to rock the more than 50 stages include Kings of Leon, Avicii, Limp Bizkit, Interpol, Infected Mushroom, The Maccabees, Hollywood Undead, Goran Bregovic, Enter Shikari and Erotic Market. The festival will also showcase emerging talents such as sizzling French art collective Fauve and award-winning reggae outfit Wailing Trees.

Launched in 1993, Sziget features circus shows, sports competitions and movie screenings as well, among other activities.