The Hay Festival is one of the world's top literary festivals, staged in the small town on the Wales-England border.
But as the 2011 event gets under way, how much do you know about it and the Powys town that plays host?
1. Hay Festival has inspired other similar cultural events over the past decade. Festivals, run the the organisers of Hay, are now staged in exotic locations such as India, the Maldives and Mexico. New destinations for 2011 include Cape Town in South Africa, Xalapa in Mexico and the south Wales town of Merthyr Tydfil.
2. Admission to the Hay Festival is free to students.
3. Half of the festival's audience comes from Wales.
4. The children's version of the festival is known as Hay Fever.
5. Two former US Presidents have visited the festival - Bill Clinton in 2001 and Jimmy Carter in 2008.
6. The late singer-songwriter Ian Dury rewrote the lyrics to "Hit Me With Your Rhythm Stick" at Hay in one of his last concerts: "From the gardens of Bombay, all the way to lovely Hay".
7. There have been some memorable quotes at the festival. Here are a few: "The Woodstock of the Mind" - former US President Bill Clinton.
"Is that some kind of sandwich?" - Arthur Miller, American playwright.
"In my mind it's replaced Christmas" - former Labour cabinet minister Tony Benn.
"One of the finest, most thought-provoking literary gatherings I've ever attended" - Junot Díaz, Dominican-American writer and creative writing professor.
8. There are about 30 bookshops in Hay-on-Wye.
9. Including Hay Festival, there are 10 other festivals and shows in the town, including Hay-on-Wye Food Festival, Hay Arts and Crafts Festival, Hay-on-Wye Horse and Pony Show and Hay-on-Wye Winter Food Festival.
10. Hay-on-Wye's population is about 1,500.
11. Hay has a Welsh name, Y Gelli (The Grove), and this appears on signposts in the area.
12. Before its bookshops and literary festival, Hay-on-Wye achieved notoriety for all the wrong reasons when in 1922 Herbert Rowse Armstrong, a local solicitor, was hanged for his wife's murder.
13. Hay's Three Tuns Pub is said to have welcomed famous and infamous visitors, including musician Jools Holland, singer Marianne Faithful, politician Lord Kinnock, BBC news presenter Huw Edwards and some of the Great Train Robbers.
14. Hay Festival is said to have been founded around a kitchen table in 1987.
15. The festival has been held at a variety of venues, including the town's primary school.
16. Hay is said to be the world's first book town.
17. Richard Booth is credited with transforming the town into a global attraction for second-hand book lovers after opening his first shop in 1962.
18. On 1 April 1977, Mr Booth proclaimed Hay an independent kingdom and he was crowned king and ruler of the new state. His horse was named Prime Minister.
19. Over the last three decades, Hay Festival's audience has grown from 1,000 people to up to 250,000 visitors.
20. The town of Hay is twinned with Timbuktu in Mali.