1. On May 21, 1961, the Freedom Riders, a group of civil rights activists, arrived in Jackson, Mississippi. They were met with violent opposition, including being attacked by a mob and arrested by police.

2. On May 21, 1881, the town of Meridian, Mississippi was destroyed by a fire. The fire started in a livery stable and quickly spread due to strong winds. Over 100 buildings were destroyed, but no lives were lost.

3. On May 21, 1917, the Great Mississippi Flood began. Heavy rains caused the Mississippi River to overflow its banks, flooding large areas of Mississippi and other nearby states. The flood lasted for several months and caused significant damage and loss of life.

4. On May 21, 1956, a plane crashed in Tupelo, Mississippi killing over 30 people, including musician Jimmie Rodgers' widow and daughter. The crash was caused by a severe thunderstorm.

5. On May 21, 1861, Mississippi seceded from the Union, becoming the second state to do so after South Carolina. This was a significant event in the early stages of the American Civil War.