What is creativity?

Sir Ken Robinson, in his book "Out of Our Minds: Learning to be Creative" says "creativity is applied imagination and innovation is applied creativity". 
He goes on to describe Las Vegas as being a city that serves no purpose BUT imagination: it's not near a harbour, on fertile ground or even in a good defense position...it's just an entire city built on imagination (Elvis impersonators?). 
Imagination is what differentiates us from animals (as far as we know).
So what is imagination?  Simply put, it's thinking of something that isn't present to the senses.  This can mean inventing a new mode of transport, planning your next vacation, or even taking your opponent's point of view in an argument.  In a way it's one of the emotional intelligences; in another way, it's a muscle that can be flexed.  Either way, it means that everyone is born with imagination...what it needs is to be nurtured to become creativity and then innovation.