One hundred years ago today, at 11pm precisely, Britain declared war on Germany.
There were few that day who could really anticipate the scale of the destruction that would follow (indeed, there was a widespread perception that the war would be quick and decisive) but the thoughts of Sir Edward Grey, the then Foreign Secretary, have become the most famous reflection of those who were there. "The lamps are going out all over Europe," he said. "We shall not see them lit again in our lifetime."
In the 100 years since that day, the accuracy of Sir Edward's remark has been proved beyond doubt. Not only did the consequences of the First World War continue to be felt long after Sir Edward's lifetime, they were still influencing events at the end of the 20th century and arguably still are.
The rise of Nazism and the Second World War, for instance, happened largely because the Germans felt humiliated by the treaty they were forced to sign in 1918 and in many ways, the First and Second World War should be seen as one long conflict rather than separate wars. The shape of the modern world can also be explained by the Great War: the decline of the British Empire, the rise of the Soviet Union and the US, the redrawing of the map of eastern Europe, the creation of the EU; all of these are ripples from 1914-18.
The effects of the war were also felt in almost every home in Britain. In all, there were 1,676,037 casualties among the British armed forces, one in ten of whom were Scottish, and in the years that followed, thousands of communities erected memorials in the most extraordinary act of communal mourning the country has ever seen.
Today, the whole of the country will be remembering again in a series of events beginning with a service at Glasgow Cathedral and ending with the gradual extinguishing of lights after 10pm. There are some who feel uncomfortable with this and ask why we are commemorating the start of a horrific war, but it must be right that the country, soberly and sombrely, remembers not only the men who were killed, but also reflects on the reasons the war started 100 years ago.
Such a reflection is not easy. Unlike the Second World War, there is no simple explanation and even dismissing the war as senseless is problematic when so many of the men in the trenches did not see it that way.
Historians are also divided over who should bear responsibility for the deaths. The late Alan Clark accused the British command of incompetence; Sir Max Hastings on the other hand says Germany was largely to blame and that British neutrality was not an option; and Christopher Clark suggests the European powers entered the war as sleepwalkers, unaware of what they were starting.
Today is a chance to continue this conversation in the hope, perhaps, that there will be no more sleepwalking and similar conflict can be avoided in future (even as it rumbles dangerously on in Ukraine and elsewhere). Above all, though, the events across the country provide an opportunity for contemplation of the 10 million people who died. There is no celebration today, only remembrance and regret.