The other day, half a million plastic balls bounced down the Spanish Steps, one of Rome's most visited and historic public places. Many visitors, picture-takers and members of the media were caused to wonder 'what's up with all these balls?'

The other day, half a million plastic balls bounced down the Spanish Steps, one of Rome's most visited and historic public places. Many visitors, picture-takers and members of the media were caused to wonder 'what's up with all these balls?'