1. Mississippi was admitted to the United States on May 20, 1817, becoming the 20th state in the union. Prior to its statehood, the region had been part of the Mississippi Territory, which was established in 1798.

2. On May 20, 1861, Mississippi officially seceded from the United States, becoming one of the founding members of the Confederate States of America. The state played an important role in the Civil War, with numerous battles and skirmishes fought on its soil.

3. In 1933, the Bonnet Carré Spillway was completed on May 20, providing flood control for the lower Mississippi River Valley. The spillway, which is located in St. Charles Parish, Louisiana, is activated during times of high river flow, diverting excess water into Lake Pontchartrain.

4. On May 20, 2013, a mile-wide tornado struck Moore, Oklahoma, killing 24 people and injuring over 200 more. The storm was part of a larger outbreak of severe weather that swept across the Midwest and South, causing widespread damage and destruction.

5. Finally, May 20 is also celebrated in some parts of Mississippi as "Emancipation Day," commemorating the date in 1865 when Union General Gordon Granger arrived in Galveston, Texas to announce the end of the Civil War and the abolition of slavery. While Mississippi was not directly affected by this event, many African Americans in the state still mark the occasion as a symbol of their emancipation and progress.