Wrigley Field was added to the National Register of Historic Places last week, a long-awaited move that made the Ricketts family eligible for massive tax credits. According to the National Park Service website, a 20% income tax credit is available for the rehabilitation of historic, income-producing buildings as long as that work complies with certain standards. That the Cubs were able to meet those criteria despite sweeping changes to the ballpark is a testament to the meticulous work put in by former VP of Restoration and Expansion Carl Rice and his crew.