Leslie Clark: 10,000 year old paintings

I've just returned from Algeria visiting an amazing explosion of creativity. Hundreds of paintings and petroglyphs made 7-10,000 years ago. The area is now a harsh desert where no one can survive,  but then it was then home to cattle, elephants, giraffes, rhinos, antelopes and ostrich—all depicted on the rock faces. What inspired such a burst of creativity that lasted over 5,000 years? I have a journal full of watercolors and hundreds of photographs that will soon inspire paintings.