Info from Wikipedia
The Green Man Festival is an independent music, science and arts festival held annually in mid-August in the Brecon Beacons, Wales. Green Man has evolved into a 25,000 capacity week long event, showcasing predominantly live music (in particular alternative, indie, rock, folk, dance and Americana). The festival site is divided into 10 areas, hosting literature, film, comedy, science, theatre, wellness and family acts.
Green Man Festival was founded by Jo Bartlett and Danny Hagan as a 300-person one-day event at Craig-y-Nos Castle, Brecon, in 2003. The festival moved to Baskerville Hall, outside Hay-on-Wye, for a two-day event in 2004, and by 2005 it had evolved into a three-day event.
In 2006 the team moved the festival to its current location on Glanusk Park near Crickhowell, in the Brecon Beacons National Park in Wales and increased Green Man to a 6,000 capacity festival.