It may seem no different from the many other enormous equines carved into England’s chalk downs, but this particular geoglyph is truly a hill horse of a different color.

The Kilburn White Horse is on Sutton Bank near Kilburn in North Yorkshire, just on the edge of the magnificent North York Moors National Park. At 318 feet long and 220 feet tall, it’s the largest and most northerly white horse hill figure in the United Kingdom. It was created in 1857 and constructed by a local schoolteacher and his students.

To some hill figure purists, this colossal white horse is a fake. Unlike the other geoglyphs in England, this elephantine equine was carved into a steep gray limestone hill instead of a traditional chalk hill. Once its shape was dug out of the earth, white chalk chips were carted in to give the horse the signature ivory color.

As such, the hill horse—dubbed the “Old Gray Mare” because of its true hue—needs quite a bit of careful grooming to maintain its snowy sheen. In the past, new chalk chips were dumped onto the figure to freshen it up. But it was soon feared that if any more chips were added, all the weight would cause the horse to start slipping down the hillside. Now, the geoglyph gets sprayed with a coat of white masonry paint every few years.

Traditionally, these touch-ups were done by a dedicated stable of local volunteers. But in 2018, the Forestry Commission, citing health and safety concerns, decided to take the reins on any future conservation work.