Kitchi Gami, Lake Superior, Lac Supérieur—the greatest of the Great Lakes. An immense body of water that has shaped the climate, culture, and economy of its region. With a population of roughly 122,000, Thunder Bay is the largest city on the lake and marks the end of the Great Lakes St. Lawrence Seaway—a waterway that extends 3,700 km (2,340 miles) to the Atlantic Ocean.