March 10 is known as Three Flags Day in St. Louis,...  ...in St. Louis, Missouri. The city was part of the Louisiana Purchase in 1803, which expanded the US into what later be...

The United States bought 828,000 square miles in 1...  ...miles in 1803 when Thomas Jefferson agreed to the Louisiana Purchase . The U.S. had only sought to buy New Orleans, but...  ...irst was infrastructure: when the U.S. bought the Louisiana territory, New Orleans had no paved roads, no str...