1803: The U.S. Senate ratifies the Louisiana Purchase Treaty, under which the U.S. pays France less than 3 cents an acre for 828,000 square miles of territory stretching from the Mississippi River to the Rockies and from the Gulf of Mexico to the Canadian border. In the stroke of a pen, the United States nearly doubles in size, and a huge frontier of opportunity opens for its citizens. The U.S. finances the deal by borrowing $11.25 million in 6% bonds from European investors.