(Reuters) - The Rolling Stones will play at Britain's Glastonbury music festival for the first time this weekend, joining Arctic Monkeys and folk band Mumford & Sons as headline acts at the five-day event.
The world's largest open-air music festival opens its gates on Wednesday with up to 135,000 people expected daily at the massive, rural site in southwestern England.
The Rolling Stones' performance on Saturday is one of a series of concerts marking the band's 50 years in the music business.
Here are some facts about the festival that started in 1970:
* WHERE IS IT - The festival at Worthy Farm, Pilton, southwest England covers 900 acres in the "mystical" Vale of Avalon where legend claims King Arthur was buried, Joseph of Arimathea walked and where ley lines converge.
* WEATHER - The festival is notorious for its torrential rain after three washout years in 1997, 1998 and 2005 in which the entire festival site on Michael Eavis's farm became a slippery quagmire.
* THE FIRST FESTIVAL - The first festival, the Glastonbury Fayre, was held in September 1970 over a two-day period with acts including Marc Bolan, Keith Christmas, Stackridge and Al Stewart. Around 1,600 people paid one pound to attend with free milk included in the admission price.
* PYRAMID STAGE - The main stage, the "pyramid" stage, was first constructed in 1971 out of scaffolding and metal covered with plastic sheeting. The structure was built close to the Glastonbury Abbey/Stonehenge ley line and over the site of a blind spring. Acts included David Bowie, Joan Baez and Fairport Convention watched by an estimated 12,000 people.
* NAME - In 1981 the festival name changed from Glastonbury Fayre to Glastonbury Festival and the decision was taken to build a permanent Pyramid stage which doubled as a cowshed and animal feed store during the winter months. Early festivals were closely linked to the Campaign for Nuclear Disarmament and during the 1980s organizers had to seek licenses following the introduction of a local government act to regulate such events.
* EXPANDED SITE - In 1985 the size of the site was increased by 100 acres as neighboring Cockmill farm land was purchased and the steadily increasing attendance figure saw 40,000 revelers.
* CLASHES - 1990 saw clashes between security teams and travelers which resulted in 235 arrests and became known as the Battle of Yeoman's Bridge. 1992 saw 250,000 pounds of donations to Greenpeace and Oxfam as organizers shifted the emphasis away from nuclear disarmament with the end of the Cold War.
* ATTENDANCE - The 1998 festival broke the 100,000 attendance mark despite a second year of quagmire conditions.
* 2013 - This year's line-up also includes British rapper Dizzee Rascal, rock band Primal Scream, Australian rocker Nick Cave & The Bad Seeds, singer Elvis Costello, veteran American country singer Kenny Rogers and British folk-rocker Billy Bragg among others.
(Reporting by David Cutler, London Editorial Reference Unit)