This is what we found on Wikipedia regarding the Llangollen International Musical Eisteddfod:

The Llangollen International Musical Eisteddfod is a music festival which takes place every year during the second week of July in Llangollen, North Wales. It is one of several large annual Eisteddfodau in Wales. Singers and dancers from around the world are invited to take part in over 20 competitions followed each evening by concerts on the main stage. Over five thousand singers, dancers and instrumentalists from around 50 countries perform to audiences of more than 50,000 over the 6 days of the event.

Famous performers at Llangollen have included Luciano Pavarotti (who first competed in Llangollen in 1955 with his father and a choir from their home town Modena, and for whom the Eisteddfod's principal trophy – the Choir of the World Pavarotti Trophy – is named), Red Army Ensemble, Julian Lloyd Webber and Ladysmith Black Mambazo. The final Sunday Evening Gala Concert has featured Katherine Jenkins, Bryn Terfel, Kiri Te Kanawa, James Galway and Montserrat Caballe.