Narrated by Julie Walters, this week we're on an adventure in Wales with its breath-taking landscapes of mountains, valleys, beaches and spectacular coastline. Ben Fogle goes wild swimming in the lakes of Snowdonia. Ray Mears witnesses a rare sight for bird lovers on the banks of the River Wye. Robson Green is paddle-boarding on the Isle of Anglesey, and in beautiful Pembrokeshire, Liz Bonnin takes the plunge with a daring sport.