The brain, as many people have observed, many times, is an incredible thing.
Amongst all the usual day to day remembering of stuff: where did I put my glasses, don't put unleaded in the car, must buy more milk, etc etc, there are all the stored away useful memories that surface every now and then such as recalling how wide/tall a transit van is when you hire one (although this can fail) how to play badminton after twenty years, and how to say 'can I have the bill' in Greek/Bulgarian/Russian-whatever.
Another whole category of recollections, distant and recent are also stored: peoples faces and names; names of plants, the best route into the centre of Birmingham, the best way to unblock a sink, get a tique off a dog, get strawberry jam to set; useless info about who won the Eurovision song contest in 1983, how many haircuts David Beckham has had, exactly what Bill Clinton did with cigars, and so on, for many decades.
Then there all the Sudden Surprise memories; ones that just surface and you had no idea they were there, occupying some bright red filing cabinet in the back of your head.
Standing in a place called Badbury Rings in Dorset recently, one of those very memories appeared in my mind as clear as when I had actually been standing at that grassy hill fort forty or so years ago.
It had been a day similar to the one in my photo, but the field full of movement, as horses pounded up the incline, then to spring over one of the brush jumps in a continual curving motion, clods flying and the air thick with thudding sounds and warm horse skin smells.
Odd that for all those years that memory had never surfaced. There it was, as clean and brightly polished as it had been stored away at that point in time.