I saw this post on Colossal and just loved it. (Though to be entirely honest it took a few minutes for me to realize exactly what I was looking at.) This is street art meets optical illusion - and I'm heartily for anything that helps adults feel like kids again - even if just for a moment.
This is in Paris (but of course) as part of an exhibition called In_Perceptions at Le 104.
Colossal has a wealth of beautiful images. Go look at them. Go!