1. The Missouri Compromise was passed on December 16, 1820, which allowed for the admission of Missouri as a slave state and Maine as a free state, and also established a boundary line prohibiting slavery north of the 36°30′ parallel.

2. On December 16, 1864, Union forces under Gen. William T. Sherman burned the city of Camden, Missouri during the American Civil War as part of his march through the South.

3. The first steel-frame skyscraper west of the Mississippi River, the Commerce Trust Building in Kansas City, was completed on December 16, 1914.

4. St. Louis International Airport (now Lambert-St. Louis International Airport) opened on December 16, 1956, serving as the main hub for TWA until its merger with American Airlines in 2001.

5. On December 16, 2008, Neil Armstrong, the first person to walk on the moon, visited the University of Missouri-Columbia to speak about his experiences in space and the future of space exploration.