humanity Read up on some facts about St. Louis, the Gateway to the West (16 Photos) By: Chase In: Facts, Humanity, Interesting May 30, 2017 435 Liked! 54 Disliked 0 1 The Gateway Arch, Built as a monument to the westward expansion of the United States, is the tallest man-made monument in the Western Hemisphere. Like this post? 435 Liked! 0