As Radio One's Big Weekend decends on Wales for the biggest free party in Europe, the station's Welsh presenter Bethan Elfyn, from BBC Introducing, takes a look at the country's biggest musical export of the last decade: rock.

Heading into the heart of the South Wales Valleys towns of Merthyr, Pontypridd, and Bridgend, Bethan finds out why so many bands from Lostprophets to The Blackout to Kids in Glass Houses want to make such epic noise.

In their own words, this is the story of how Welsh rock took on the world. Like Zane Lowe said, "There's something in the water!" Show less