It extends from the Atlantic to the Pacific and northward into the Arctic Ocean, covering 9.98 million square kilometres (3.85 million square miles), making it the world’s second-largest country by total area. Its southern and western border with the United States, stretching 8,891 kilometres (5,525 mi), is the world’s longest bi-national land border. Various Indigenous peoples inhabited what is now Canada for thousands of years before European colonization. As a highly developed country, Canada has the seventeenth-highest nominal per-capita income globally as well as the thirteenth-highest ranking in the Human Development Index. Its advanced economy is the tenth-largest in the world, relying chiefly upon its abundant natural resources and well-developed international trade networks.