In the midst of one of the wealthiest counties in the United States, Troy, Michigan is a thriving center of business, particularly in the automotive and financial sectors, and is home to a number of major companies. Based on property value, Troy is the second largest city in Michigan, second only to Detroit. The Top of Troy is the city's tallest building (now renamed the National City Center). Troy is home to the upscale Somerset Collection mall, featuring a skywalk and over 180 stores, and the Oakland Mall.