The skies over Normandy will once again be filled with parachutes as those who were first to land in Nazi occupied region are honoured.
Tourists at the world famous landmark were treated to an unexpected sighting of Prince Harry as the royal took in some of Italy's sights.
Speaking exclusively to ITV News, Harry says it "makes no sense" that one of the Second World War's bloodies battles has been "forgotten".
The Duchess of Cambridge donned a pair of headphones and tried to interpret codes during her visit to Bletchley Park where her grandmother worked.
Valerie Glassborow worked as a civilian member of staff, probably as a duty officer, alongside her twin sister Mary.
Wearing an Alexander McQueen outfit, Kate greeted staff on a visit to mark a year-long restoration project at the Buckinghamshire site.
The Duchess of Cambridge is due to visit Bletchley Park where she will meet with a code-breaker who worked with her grandmother during the Second World War.
Code-breaker veteran Lady Marion Body recalls working alongside the Duchess' paternal grandmother Valerie Glassborow at the famous 'spy school', where codebreakers were credited with shortening the war by at least two years.
Miss Glassborow, as she was known before marrying Kate's grandfather Peter Middleton, worked as a civilian member of staff, probably as a duty officer, alongside her twin sister Mary.
Kate's solo visit will mark a year-long restoration project at the Buckinghamshire site.
Veterans of the Battle of Monte Cassino gathered alongside Prince Harry today to mark 70 years since one of the costliest battles of the Second World War.
While Harry praised their courage, one veteran of the Italian assaults told ITV News: "I never thought I would come out of it alive".
ITV News Royal Editor Tim Ewart reports:
Prince Harry has told ITV News it "makes no sense at all" that the Battle of Monte Cassino is referred to by some as the "forgotten campaign" - insisting the veterans of one of the Second World War's bloodiest battles deserve "as much recognition" as anyone else that served in the conflict.
Speaking to Royal Editor Tim Ewart at the site of the assaults, Harry praised the heroism of those who fought for months on end "knowing that they were going to lose most of their friends and probably themselves as well".
A 90-year-old veteran has spoken of how he faced the horrors of Monte Cassino aged just 18.
Ivor Gaskill, who served with the Royal Hampshire Regiment as a private, said: "I remember trying to get up the hill - we were up to our waists in mud and water, soaking wet, hungry and full of lice.
"We were being shelled and shot at constantly but it was just a case of keep going. What else was there to do? You couldn't run away.
The veteran who returns each year to the site where so many of his friends died - welcomed Prince Harry's visit, saying: "I thought we were forgotten.
"It's great to see him here. It's marvellous of him to do it."
Prince Harry left a personal tribute to the British soldiers who lost their lives at the battle of Monte Cassino.
The prince took part in a memorial service to mark 70 years since the battle and left a wreath with a note, saying: "In memory of all those who paid the ultimate sacrifice for our country. Thank you."
Prince Harry has taken part in a memorial service 70 years on from one of the Second World War's bloodiest battles.
On the second day of a two-day visit to Italy, Harry took part in a procession and met veterans of the battle of Monte Cassino - a brutal clash which saw around thousands of Allied and Axis soldiers lose their lives.
The prince, who himself serves in the Household Cavalry, also laid a wreath for the British soldiers who died during the fight to take control of the strategically important monastery above the town of Cassino.
As well as British forces, a number of Commonwealth soldiers took part in the battle, along with forces from the USA, Poland, France royalist Italian troops.