法 Brian Vikander/Corbis Great Slave Lake, Canada Great Slave Lake is the largest lake in Canada and the deepest lake in North America. As the source of the mackenzie river it lies at the head of one of the world's great waterways• Brian Vikander/Corbis • Great Slave Lake, Canada • Great Slave Lake is the largest lake in Canada and the deepest lake in North America. As the source of the Mackenzie River, it lies at the head of one of the world’s great waterways