How to tag a modern era menhir?

Since the day humankind discovered rocks they arranged them in special configurations. One is known as menhir .

Apparently around 45 B.C. some guy in the in the Armorica region in northern Gaul ran a successful business, making, selling, and delivering them by hand. But even today people still like menhirs. People errect long stones or rocks in an upward position. Which poses the question:
How can I tag such a modern day “menhir”? Obviously not an archeological site, and neither the tag historic:civilization=* allows for the modern era European civilization.

I’d consider this as artwork:
Maybe something like ?