1. On September 15, 1915, the Missouri State Capitol building in Jefferson City caught fire, destroying much of the interior of the building. The cause of the fire was never determined, but it was believed to have started in the House of Representatives chamber.

2. On September 15, 1947, the first flight of the McDonnell XF-88 Voodoo took place at Lambert Field in St. Louis. The XF-88 was the first American-designed swept-wing jet fighter, and it paved the way for later aircraft like the F-86 Sabre and the F-100 Super Sabre.

3. On September 15, 1987, the St. Louis Cardinals clinched the National League East division title with a 4-3 victory over the Montreal Expos. The Cardinals went on to win the NLCS that year, but lost to the Minnesota Twins in the World Series.

4. On September 15, 2000, the Gateway Arch in St. Louis was closed to the public for several months due to a renovation project. The renovation included the installation of a new tram system to take visitors to the top of the arch, as well as other improvements to the visitor center and surrounding park.

5. On September 15, 2020, Missouri Governor Mike Parson visited Joplin to announce the completion of the city's new Mercy Hospital Joplin. The hospital was built to replace the previous one, which was destroyed by a tornado in 2011. The new facility is one of the largest hospitals in the state, with over 900,000 square feet of space.