D-Day: The Ultimate Conflict (five): Three elderly men approached each other on a beach. "Good morning, how are you?," asked one, as they shook hands and exchanged friendly greetings.

The British man, the American and the German met for the first time at the end of this two-hour documentary about Operation Overlord - when 200,000 Allied troops stormed the beaches of Normandy in the greatest invasion in history.

All three, along with other survivors, shared their memories of the build-up to D-Day and the battle itself. Archive footage, reconstructions and personal recollections added up to a good way of marking of the 60th anniversary.

The latter part concerned itself with the battle itself, while the first half concentrated on the three-year build-up to the invasion. Particularly fascinating were the "inventors, mavericks and forgotten army" who created a top secret armoury, to smash through Hitler's defences. Anticipating a seaborne attack, the stretch of open beach was strewn with deadly obstacles.

The Allies' had to find ways to neutralise these hazards. For example, a boat builder in New Orleans - whose boatyard was not on water, but the main street - used his experience in providing fast boats for rum runners to perfect an assault craft.

He'd built it to skim over floating obstacles, such as logs and mangrove roots, in the Mississippi. His amphibious landing craft, with waterproof ramps based on a cigar box design, was just what the navy needed to evade traps in the water.

He'd even had the foresight to buy the entire 1939 crop of mahogany from the Philippines that could be used to make the boats as steel was in short supply. Eisenhower called him "the man who won the war for us". Hitler called him "the new Noah". Fears for his life, recalled his daughter, led to permanent guards being posed outside the family home.

The Archimedes principle was used to develop the DD tank, which could "swim" under its own steam to shore.

A fun fair ride at the 1939 World Fair in New York was the inspiration for training the US paratroopers needed to drop behind enemy lines to take control of villages and roads behind the beaches. The tower, from which members of the public parachuted 250 ft down to the ground, was rebuilt at the military jump school.

Even more ingenious was the range of customised tanks, fitted with mechanical devices to deal with obstacles, such as mines buried in the sand and fields of barbed wire, left in their path by the Germans. One tank laid a carpet - fabric reinforced with wire netting - to enable tanks to travel over the unstable sand.

How to stage a surprise raid in order to take two heavily-guarded bridges in the early hours of D-Day was solved by flying soldiers aboard silent gliders, or "airborne coffins" as they were known. Pilots found themselves flying a wooden aircraft without any engine seven miles in darkness and landing on an area half the size of a football pitch.

As history tells us, D-Day didn't all go according to plan in all respects. Thousands lost their lives. But this documentary, with moments of humour and horror, was a compelling reminder of "the longest day".

Published: 04/05/2004