A New Zealand pilot who took part in the Dambusters raid 70 years ago says the crews were well briefed on the top-secret mission.
Twenty specially modified Lancaster bombers from RAF 617 Squadron took off from a base in England on a raid deep into Germany on 17 May, 1943, to attack dams in the Ruhr Valley using bouncing bombs.
The dams powered Germany's industrial heartland and it was felt their destruction would inflict huge damage on the German war effort.
Les Munro still remembers the pre-mission briefing, which included Barnes Wallis, the inventor of the bombs, explaining what they were all about.
But Mr Munro and his crew never made the target as they were hit by enemy flak crossing the Dutch coast and returned to base.
