There are 16 white horses carved into the hillsides in England, and nearly as many lost to history. A great many are pre-historic. No one knows why this was done but there appears to be a mythology about white horses all around the world.
This is the Kilburn White Horse, which is not nearly as ancient. A local decided his vacinity needed one in 1857. Most are located in the south of England in Wiltshire. This one is in Yorkshire. It is carved in sandstone, whereas most are carved in the white chalk hillsides. All require periodic maintenance to maintain the sharpness of image.
Gigantotomy and Leucippotomy
In 1949, Morris Marples invented the words leucippotomy and gigantotomy. Morris wrote that he "half-humorously ventured to use leucippotomy for the cutting of white horses and gigantotomy for the cutting of giants on rare occasions". Neither word appears in the Oxford English Dictionary, and rarely in the popular press. (sited from Wikipedia)