 Glastonbury Music Festival has been running for 54 years and is one of the biggest in the world with nearly a quarter of a million attendees. The main, Pyramid Stage, has seen the most famous music acts from across the globe, thrilling audiences with blistering sets, ecstatic sing-alongs, glitzy productions. At this year's festival, Marina Abramovich was invited by the organisers, Michael and Emily Evis, to create a work for the Pyramid Stage.