I'm a big fan of art spaces, museums and galleries, but any other indoor or outdoor venue may qualify. While art spaces need art objects, art objects need art spaces to have a powerful effect. But increasingly I see the visitors of art spaces, deeply immersed in the experience or maybe just going through the motions, as art objects in themselves. It is a form of performance art because the object is constantly moving and transforming itself. Not all art is good art, of course, which applies to this category as well.
I've captured some visitors of the Thyssen art museum in Madrid against a bright background that turns them into shadow forms.