Ninety years ago, on 4 August 1914, Britain entered World War I by declaring war on Germany.
Henry Allingham, 108, is the last survivor of the Battle of Jutland
Some one million men joined the fighting in the first year of the conflict, as Britain tried to rally a formidable force to bolster its small standing army.
Henry Allingham did not rush to enlist.
"On August 4 I wasn't too troubled," he said. "I didn't realise what it really meant."
It was only later when the gravity of the situation became clear to him and the recruiting drive began in earnest, that he decided he wanted to join the fighting.
Now aged 108, Mr Allingham was one of the four World War I veterans to attend the ceremony at the Cenotaph in London on Wednesday marking the anniversary of the declaration of war.
He told the BBC he thought joining the war effort would be "an adventure".
That spirit was common among volunteers the world over - although many were soon disillusioned by the realities of war.
Mr Allingham served as a Royal Naval Air Service mechanic, flying patrols of the North Sea as a navigator and repairing aircraft and engines at the battles of the Somme and Ypres.
"It was the first time I went near a plane," he said, pointing out that the first powered flight in the world had only taken place a handful of years earlier.
He remembers the plane he flew in the war's opening months, "my baby" as he called it, with a degree of disbelief.
"They didn't have much speed with them. Sometimes they'd be coming along and the force of the wind would have you standing still. Sometimes you'd be flying backwards," he said.
Henry paid tribute to the courage of the infantry men
"You'd have to have good weather to fly.
"There were two rifles in the cockpit, that was all the armaments we had."
Mr Allingham is the last survivor of the Battle of Jutland in 1916, in which the British Grand Fleet established dominance of the North Sea, despite losing more ships on the day.
He said his ship, the Kingfisher, barely escaped destruction. A German shell ricocheted and was heading directly at the ship, when a stroke of luck handed the crew an incredible escape.
"It bounced over the top of the ship!" he said.
"Where it went I don't know but it was a saviour for us. If it hadn't [bounced], who knows, the whole ship would have been gone."
Despite the danger he faced, he thinks he had an easy time of it compared to men who served in the infantry.
"On the western front, men in the trenches stood in water up to their knees. They had to eat and sleep in that water. How did they manage?" he said.
He said those men regularly had to march for miles on end only to stop and dig trenches before marching on again.
"They were like hermit crabs," he said. "But I've always said the men in the trenches were what won the war for us."
One of those men, John Oborne of the Light Infantry, also attended the Cenotaph ceremony, despite preferring to leave his memories of the war in the past.
"You wouldn't like to know what I did," he said. "What do you go to war for? To kill people."
Twenty-three World War One veterans survive
"I thought I'd be doing some good, even though I was just a tiny cog in a great big wheel. I never gave it a thought that I'd be killing people.
Mr Allingham used to share that reticence, but shares his experiences now to honour those who died in the war, and to help the modern generation understand the horrors they witnessed.
"War's stupid," he said. "Nobody wins. You might as well talk first, you have to talk last anyway."