Transportation through the Straits of Mackinac changed dramatically over the centuries. The earliest inhabitants traveled by boat and found the Straits a convenient east-west highway linking the Midwest of the North American continent to the Atlantic world by way of the St. Lawrence River. Before the arrival of Europeans, some Native Americans spent their summers in the Straits fishing and trading, and they explored and learned the interconnected waterways that could carry them far to the west and east. When Europeans arrived, the strategic importance of the Great Lakes in the fur trade made Michilimackinac a well-known name throughout the world. Over time, the fur trade was replaced by fishing and lumbering. Once land transportation in the form of railways and highways became convenient, traffic patterns in the Straits shifted to a north-south direction, but these products and other heavy products of the last two centuries continued to move more cheaply on the water. Today, freighters still carry products through the Straits to and from the rest of the world.