The beautiful Italian city of Milan will very shortly be home to a 2.9 million-square-foot, 18-MW solar array atop the Milan Trade Fair. The array will become the largest rooftop array in the world, surpassing the current record-holder, a 12-MW array on the General Motors factory in Zaragoza, Spain.

In comparison, the largest rooftop array in the U.S. is the 2.37-MW array on the Atlantic City Convention Center.
This enormous array is expected to be completed by the end of 2010 and for a price the bargain price of between $97 and $111 million. Give or take.