Why is there a larger arch in St. Louis MO?

One year after the United States doubled its territory with the Louisiana Purchase, the Lewis and Clark expedition leaves St. Louis, Missouri, on a mission to explore the Northwest from the Mississippi River to the Pacific Ocean.

Even before the U.S. government concluded purchase negotiations with France, President Thomas Jefferson commissioned his private secretary Meriwether Lewis and William Clark, an army captain, to lead an expedition into what is now the U.S. Northwest. On May 14, 1804 the "Corps of Discovery" featuring approximately 45 men left St. Louis for the American interior.

On September 23, 1806, after almost two and a half years, the expedition returned to the city, bringing back a wealth of information about the largely unexplored region, as well as valuable U.S. claims to Oregon Territory.

And know you know why there’s a large arch in STL-it’s thegateway to the west!