I wanted to find a picture of the white horse on the hillside. The Bronze age one. The one that Terry Pratchett mentions in Wee Free Men. I found this one, which is the one I was after, but not until I had also found this one and this one (with added pranksterism) and this one which were all created much more recently than the Bronze Age.
I also discovered that there is a word for these: leucippotomy is the art of carving white horses in chalk upland areas – particularly apparent in southern England and presumed of prehistoric origin (copied directly from Wikipedia, which explains the random links to things you know perfectly well)
But anyway – how awesome is is that there exists a word only and precisely for carving horses into the chalk downs?