Plot: Matt Baker heads to Slapton Sands in Devon on the 66th anniversary of D-Day to discover how a training exercise cost 749 American troops their lives, and finds out why this area is now being used to train a new generation of military recruits. Julia Bradbury's on the freshwater lagoon which also played a part in training for the Normandy invasion to discover what's being done by modern day King Canutes to hold back the sea water and protect this fragile freshwater lake