The Detroit Institute of Arts (DIA), located in Midtown Detroit, Michigan, has one of the largest, most significant art collections in the United States. In 2003, the DIA ranked as the second largest municipally owned museum in the United States. Its art collection has been valued at $8.1 billion, according to a 2014 appraisal. With over 100 galleries, it covers 658,000 square feet (61,100 m²), making it the sixth-largest art museum in the United States; a major renovation and expansion project completed in 2007 added 58,000 square feet (5,400 m²). The museum building is highly regarded by architects. The original building, designed by Paul Philippe Cret, is flanked by north and south wings with the white marble as the main exterior material for the entire structure.