Two days of events are taking place in the UK and France to mark the 80th anniversary of the Normandy landings on 6 June 1944, when troops from the UK, the US, Canada, France and others landed in Normandy and attacked German forces.
Britain's wartime prime minister, Sir Winston Churchill, called it "the most complicated and difficult" operation of World War Two, leading to the eventual liberation of France from Nazi occupation.
In Portsmouth the UK's national commemorative event was led by Dame Helen Mirren.
She said: "The presence today of some of those who contributed to that remarkable venture is an extraordinary privilege. Your bravery remains as inspiring now as it was eight decades ago."
D-Day veteran Roy Hayward was met with a standing ovation when he walked on stage on Southsea Common.
He was severely injured in Normandy, both his legs had to be amputated below the knees. He said he represented all the “men and women who put their lives on hold to go and fight for democracy and this country”.
The Red Arrows and a pair of Dakota military transport aircraft seen with their invasion stripes took part in a fly-past.
King Charles who attended with his wife Queen Camilla, paid tribute to the veterans who embarked in Portsmouth 80 years ago.
“It is our duty to ensure that we and future generations do not forget their service and their sacrifice in replacing tyranny with freedom.”
Prince William sat alongside Prime Minister Rishi Sunak and his wife Akshata Murty.
During his address, the Prince of Wales said: “We will always remember those who served and those who waved them off. The mothers and fathers, brothers and sisters, sons and daughters who watched their loved ones go into battle, unsure if they would ever return."
Labour leader Sir Keir Starmer posed for a photo ahead of the start.
The event included a number of performances, including one by actress Emma Barton, who sang Sing As We Go, a song originally performed by Gracie Fields.
In Cumbria, lone bagpiper Richard Cowie played on the deck of a traditional steamer at Bowness-on-Windermere to honour the D-Day piper Bill Millin, who played on the Normandy beaches on D-Day to confound the enemy and boost the morale of allied troops.
Across the channel in France, ceremonies are also taking place ahead of the main event on Thursday.
Veteran Alec Penstone, 98 (above centre), was one of those at the statue of Field Marshal Montgomery during the Spirit of Normandy Trust service in Colleville-Montgomery.
French President Emmanuel Macron paid homage to the Saint Marcel maquis, a force of French Resistance fighters and the French SAS paratroopers, at an event in Plumelec, Brittany.
On Tuesday, more than 30 former servicemen made the ferry crossing aboard Brittany Ferries ship Mont St Michel, sailing out of Portsmouth Harbour to Ouistreham.
Among them were veterans Bernard Morgan (above left), from Crewe, and Jack Mortimer (above right), from Leeds, both aged100.
During the voyage veterans Harry Birdsall (below back) and Alec Penstone (below front) threw a wreath into the sea to remember those who never made it to shore during the landings in 1944.
On Sword Beach, one of the landing points for British troops, John Life and Donald Jones (above), along with other veterans and family members travelling with the Royal British Legion, were saluted by a modern RAF transport aeroplane.
Gene Kleindl, 102, from Illinois, who served as medic in the 90th Infantry Division of the US Army, arrived on the beaches of Normandy on D-Day +2. Here he visits the grave of his friend Ralph Gaddis at the Normandy American Cemetery in Colleville-sur-Mer with his granddaughter Jessica Smith.
Along the Normandy coast, people dressed in period uniforms and vehicles can be seen. Here a man gives a victory sign as he drives a US Jeep through Colleville-sur-Mer.
At the British Normandy Memorial in Ver-sur-Mer, 1,475 silhouettes form the Standing with Giants installation, each sculpture representing a fatality under British command on 6 June 1944.