US President Donald Trump and German Chancellor Angela Merkel joined the leaders of Britain, France and other nations on Wednesday to mark the 75th anniversary of the 1944 D-Day landings, which changed the course of World War II in Europe.

Trump, Merkel, British Prime Minister Theresa May, French President Emmanuel Macron and other leaders watched readings, re-enactments, song and dance performances and fly-pasts by World War II aircraft in the southern English city of Portsmouth.

Trump joined Queen Elizabeth II to meet veterans following the ceremony to mark the assault on German-occupied Normandy in western France by more than 150,000 British, US, French and other Allied troops.

The events marked the conclusion of the US president’s three-day state visit to Britain, which featured a royal welcome and a banquet hosted by the queen.

Before flying to talks in Ireland with Prime Minister Leo Varadkar, Trump tweeted that he “could not have been treated more warmly in the United Kingdom by the royal family or the people.”

“Our relationship has never been better, and I see a very big trade deal down the road,” he wrote.

In her speech at the D-Day commemoration, the queen paid tribute to “hundreds of thousands of young soldiers, sailors and airmen [who] left these shores in the cause of freedom.”

“The fate of the world depended on their success,” she added.

“Many of them would never return, and the heroism, courage and sacrifice of those who lost their lives will never be forgotten.”

The 16 nations represented in Portsmouth signed a “D-Day proclamation,” vowing to prevent any repeat of the “unimaginable horror” of World War II and “work together to resolve international tensions peacefully.”

Trump, May and other leaders are scheduled to travel to Normandy for French commemorations of D-Day on Thursday.

One former soldier, 99-year-old John Jenkins, took to the stage to say he was “terrified” when he joined the D-Day operation.

“I was terrified, I think everyone was,” Jenkins said. “I was just a small part in a very big machine.”

Trump read from the prayer that Franklin Roosevelt, the US president in 1944, broadcast by radio to tell people US soldiers had “set upon a mighty endeavour, a struggle to preserve our republic, our religion, and our civilization, and to set free a suffering humanity.”

Macron thanked the veterans “on behalf of my nation.” He read the final letter written by French resistance fighter Henri Fertet, who was executed at 16 years old.

May said earlier that Wednesday’s event would “reaffirm the enduring importance of the Western alliance and the shared values that underpin it.”

British opposition Labour leader Jeremy Corbyn said the D-Day troops had shown “unimaginable heroism.”

“Many laid down their lives in the fight against fascism,” Corbyn said. “We must … honour them by opposing the forces of hatred today.”

After talks with May on Tuesday, Trump said Allied soldiers were “heroes who laid down their lives to rescue civilization itself” from Nazi Germany.

He said the United States and Britain had built “the greatest alliance the world has ever known.”