A Ballet related question?

I don't dance. At all. But on the way to the grocery store I spotted a bunch of ballerinas doing that ballet thing in which one curves their body to one side, arm over the head, and goes on their toes. But they were doing it in a very confined underpass sidewalk, with a low roof and a walls on either side. Why would they be doing this in such a strange place, right next to a busy road in broad (morning) sunlight? It seemed odd to me.