On this day 100 years ago Britain declared War on Germany and entered what would become known as the Great War, a war that would claim an estimated 750,000 British military lives.
Today around Britain and Europe, commemorations are taking place to remember the sacrifices and bravery of those who fought in the First World War.
In Norwich The Forum's exhibition, 'The Day We Went To War', details the contributions and sacrifices made by local people in the devastating conflict.
People have already been flocking to the exhibition to add their own thoughts and tributes to notelets that will form part of the display.
We asked them why the war should be commemorated.
Judith Parks, who lives on the outskirts of Norwich and is retired, said: 'It is important to remember those who gave their lives and your own relatives who died for the country.
'It feels sad commemorating something so awful on such a sunny day, but in doing so it would be nice to think it would prevent further wars like this from happening again.
'My grandmother's brother died during the war and I am currently researching when and where that was.'
Mike Spivey, 65, from Thorpe St Andrew, said: 'A huge number of people died from both sides and everybody thought they were correct. The war created changes all over Europe.'
Colin Blakemore, 71, from Norwich, a retired overseas aid worker, said: 'My grandfather died on the Irene, a ship that was sunk in the Thames Estuary by a mine. And two of my uncles were killed, one in a submarine and another I'm not sure how he died.
'You should always think about it, it's sad. But everyone in this country should know what the country and those who fought for it went through to be where we are now.'
Tony Gray, 67, retired, from Norwich. Both Mr Gray's grandfathers fought in the war, one with the Suffolk Regiment and the other with the London Scottish Regiment, both returned home. His grandmother knew the Houseago family, their son Private Albert George Richard Houseago, is commemorated in the Forum exhibition. He said: 'We should remember. It will happen again, as men will be men.'
Betty Ball, 91, a retired lecturer from Earlham, said: 'You would hope that there would never be another war like that again. My father could not fight in the war because he wore glasses, but he worked with the Royal Engineers in Iraq building railways.'
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