How to tag Mountain Monograms

It’s a popular thing to do in rural american towns to put the initials of the town in big letters on a hillside visible from the town. These are often called "mountain monograms’. Looking at several in OSM I see them tagged as monuments, tourist attractions, artwork etc. Any suggestions on how these points of interest should be tagged in OSM.

Here’s an example of one that is not yet tagged in OSM: 36° 36′ 9.72″ N, 118° 5′ 15″ W