The 75th anniversary of D Day is tomorrow, June 6.
It was on that date in 1944 that the largest ever seaborne invasion took place.
The UK element to the commemorations will be held today in Portsmouth, from where much of the allied force departed across the Channel.
Some 150,000 service personnel took part in the operation. That a colossal 24,000 troops were parachuted in to Normandy in the hours before dawn on June 6 is one statistic that gives a flavour of the scale of the American-led plans.
The allied forces could have invaded the year before but deliberately delayed any attempt until they could amass a force that was almost certain of success.
D Day was ultimately a success but it was many weeks, and many tens of thousands of deaths, before this was assured The Nazis would not be entirely defeated for another year.
Theresa May will be joined by leaders from all the countries that fought alongside the UK in Operation Overlord, including President Donald Trump of the United States, at the tail end of his state visit to the United Kingdom.
It might seem strange to some observers that the German chancellor, Angela Merkel, will be present, given that the culpability of her country for the fact World War II happened is undisputed. But few nations in history have accepted their blame for a major historical event in the way that Germans have come to do with regard to that global conflict.
The main commemorations will be tomorrow, in France.
Each year, the number of veterans of D Day is dwindling. A participant who turned 18 in June 1944 would now be 93. Most survivors are a few years older than that.
On the 70th anniversary, the News Letter interviewed a wireless operator, William Cooke from Co Armagh, who was there that first invasion day, and recalled seeing dead bodies floating in the water. Aged 18 on D Day, he has since died.
Today will be in honour of people such as him, whose military service helped usher in the decades of peace since 1945.