Complex sentence: His plan was to strike back at the Germans as best he could-by organising mass break outs from the POW camps he was in, one became known as The Great Escape, which was planned to allow 200 men to escape on a single night.
Split into simpler sentences: His plan was to strike back at the Germans as best he could-by organising mass break outs from the POW camps he was in. One of them became known as The Great Escape, which was planned to allow 200 men to escape on a single night.