First stop Make this among the first stops on your tourist itinerary, as the Arch will provide both the historical context (through its Museum of Westward Expansion) and the geographic overview (through the breathtaking view from the top) for your Gateway experience. Kids' stuff After your historic introduction downtown, hop aboard the mini-gauge railroad of the St. Louis Zoo, which blends elements of its 1904 World Fair heritage with modern animal facilities, such as the newly opened Penguin and Puffin Coast.