Montana has many natural and man-made attractions. It has over 200 lakes for swimming and mountains for winter sports. Two thirds of the state is covered in mountains, with Granite Peak reaching over 3,900 meters tall. Notable constructed landmarks include Fort Peck Dam, one of the largest earth-filled dams, and Bannack Ghost Town, a popular tourist attraction. Gold mining has been important economically in western Montana. Cities include the capital Helena and Butte, which supplies a third of US copper. Vacationers can enjoy the Montana State Fair in Butte or visit the largest city, Great Falls.