The St. Lawrence is arguably the grandest and the richest of Canadian rivers. It has become part of our national consciousness. Running for 1,207 kilometres, it is a transportation highway, a refuge for wildlife, Central Canada's playground, and a reservoir of history. The St. Lawrence brought the earliest European explorers to a new land. Four national parks lie within its reaches. The St. Lawrence is a great river and estuary that, together with the Great Lakes, forms a hydrological system that penetrates 4,000 kilometres into the heart of the continent. It is a vital artery for the most populous area in Canada and one of the busiest shipping routes in the world.