I love public art. By public art I don't mean that art sanctioned by city councils and governments, that's not art. There is nothing even remotely artistic about it. Governments and Jury's simply don't have the wherewithal to judge art.
No, by public art I mean art given to the people, slipped surreptitiously into their diet of news and misinformation without their knowing. Art that seeds thought. Art that raises questions.
Crop circles are one example. Some people put them down to space aliens trying to communicate with us. Personally, I subscribe to the view of a group of guerrilla artists. Whatever you think, they have become a sort of cultural meme.
Another example I'm very fond of are the Toynbee Tiles. They consist of a linoleum and asphalt blend of tile that's layered into the pavement of streets. Examples have been found in many major cities, the identity of the artist remains unknown. Typically the tiles state:
TOYNBEE IDEA
IN KUBRICK'S 2001
RESURRECT DEAD
ON PLANET JUPITER.
Or some variation thereof.
Further reading:
The NY Times (1999) on the Toynbee Tiles