The First World War was one of the deadliest conflicts in history, killing more than 16 million people.
In November 1918, after four long years, the Armistice was signed and the guns fell silent.
In a series of special reports, we'll be marking the centenary of the war.
There are more than 100,000 war memorials in Britain - most put up after the Great War.
It followed a huge outpouring of grief in towns and communities for those who had died in battle, many of whom had either volunteered willingly or been called up.
The process of remembering the dead from 100 years ago continues even today.
- Watch Derek Johnson's report
Philip Cormack's story:
WWI was the first time that large-scale battles were fought in the air.
Although the pilots of the Royal Flying Corps - later the RAF - were romantic figures to those at home, aerial combat was so dangerous that many had little hope of survival.
Paul Cormack talks about his great uncle, who was one of the pilots.