From this post:
… In Pisa my elder daughter became fascinated by all the people taking pictures of their friends holding up the leaning tower, or pushing it over – it is never easy to tell from the wrong angle. At times there were four or five people in a row all holding their hands up – which, when taken out of context, looked like some kind of mass-hallucination tai chi class.
She asked me for her camera and disappeared for a half hour, and then came back with these, which I think vie with many of the conceptual art pieces in the Whitney Museum. I found them hilarious and strangely compelling. …
Via. I observed similar behavior from teenaged boys at the Washington Monument, which involved them laying on the ground in various poses. Won’t provide a photo though; you’ll have to visualize that on your own.