1. On July 21, 1861, the first major battle in the Civil War west of the Mississippi River took place in Springfield, Missouri. The pro-Union forces were led by Colonel Franz Sigel, while the pro-Confederate troops were led by Major General Sterling Price. The Confederates were victorious in this battle.

2. Harry S. Truman, the 33rd President of the United States, was born in Lamar, Missouri on July 21, 1884. Truman became President in 1945 after the death of Franklin D. Roosevelt, and he served until 1953.

3. The Missouri State Penitentiary, which was in operation from 1836 to 2004, saw a major riot on July 21, 1954. The riot occurred when a group of inmates overpowered the guards and took control of the prison. After several hours, the National Guard was called in to restore order.

4. On July 21, 1997, the University of Missouri-Columbia became the first public university in the United States to establish a fully integrated disability program. The program aimed to make the university accessible to people with disabilities by providing support services and accommodations.

5. In 2015, Missouri Governor Jay Nixon declared July 21 as National Youth Service Day in the state. This day recognizes the important role that young people play in their communities and encourages youth service projects across the state.