Canada is the world’s second largest country by total area, occupying most of northern North America. Extending from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, Canada shares land borders with the United States to the south and to the northwest. Canada is a constitutional monarchy and a parliamentary democracy. It was formed as a confederation of British colonies in 1867 and secured effective independence in the 1920s. With a population of 35 million spread over 10 million km², and major oil supplies, Canada is one of the most prosperous countries of the world.