I once looked up a few facts about the Battle of the Somme when replying to a letter in the press.
The 90th anniversary of the battle is coming up on Saturday.
The first thing, of which my fact-checking reminded me, is how long the battle was. Many people think it took just a day or a few days.
In fact it went on for four and a half months.
It is difficult to visualise 1.2 million people.
It helps to imagine the present day populations of Glasgow, Edinburgh and Aberdeen put together. Living in those cities today there are a little over 1.2 million people.
That's how many people were killed at the Battle of the Somme.
Then you have to remember the additional hundreds of thousands maimed, injured or traumatised for life. And the hundreds of thousands who saw their friends killed and often lived with their bodies alongside them for quite a while.
The sheer horror of day-to-day life in the trenches can only be imagined.
And yet, all this, together with the equally horrifying rest of the First World War, was sparked off due to a car taking a wrong turn in Sarejevo and a set of alliances which set cousin against cousin (in the case of George V versus Kaiser Bill).
The whole thing was utter madness. Life in the trenches was hell on earth.
I am pleased to see that British schol children often visit the site of the First World war battles nowadays. This is vital. Anyone who has learned about even a thousandth of the horror of the First World War is unlikely to want to support a war in a hurry.