London 2012: Bell ringers to mark start of Olympics
Bells will be rung around the UK as quickly and as loudly as possible for three minutes on Friday morning to mark the official start of the 2012 Olympic Games.
All The Bells was the idea of Turner prize-winning artist Martin Creed, and will involve everything from church and school bells, to bicycle and door bells.
Sarah Moore visited some of the Welsh bell ringers taking part as they rehearsed for the big event.