If you dip into this list of things to do in St. Louis, Missouri, you will realize there are dozens of colossal attractions in the area — from the enigmatic pre-Columbian mounds of Cahokia to the shining Gateway Arch across the Mississippi River and everything in between to capture your imagination. Scroll down to learn what exactly makes this midwestern city a memorable trip destination, including, but not limited to, the ubiquitous "Gateway to the West" nickname.