The towering, untitled sculpture was not universally popular when it was unveiled 50 years ago. “[It] might never have been in danger of being destroyed or being replaced with a statue of Cubs baseball player Ernie Banks (per the wishes of one alderman), but for several years, the word ‘controversial’ preceded any mention of the work in the press. … Children began using The Picasso as a slide almost immediately, making it a de facto interactive sculpture.”