What hovers above the valley of ashes? Describe this and predict why it's important?

The huge sign of Dr. T. J. Eckleburg overlook the Valley of Ashes. Many critics suggest that the eyes symbolize God looking over a sinful land. In George Wilson's case the faded eyes can symbolize the death of the American dream or the American dream being an illusion to begin with. In either case, poor George Wilson has a life that is full of shattered dreams.