Someone was playing the bagpipes.
I looked through the trees onto the lower field where the picnic tables are, and there he was, a youngish man in ordinary summer casual wear, playing the bagpipes. Not the uileann pipes. The big old bagpipes. And what was strangest of all, it sounded absolutely enchanting. I've only ever heard bagpipes playing whiney military anthem-style music, but this bloke was playing the most beautiful traditional Irish stuff, and if you can think of any more suitable music to hear when tramping through a sun-dappled path surrounded by 200 year old trees, I can't imagine what it is. It was just amazing. And you could hear him all over the park, and everyone seemed to be enjoying it. There was no laughing, or eye-rolling - the music was so nice that even the usual tracksuited teenagers who turn up in the park and pretend they're not all posh private-schoolkids weren't hanging around laughing at him. I heard a little kid ask its mother what the "nice sound" was. I don't know who this mysterious piper was, but I hope he comes back.