1. Birth of Rufus Lisle: Rufus Lisle, an important figure in Kentucky politics throughout the 19th century, was born on March 21, 1817, in Garrard County, Kentucky. Lisle served as a member of the Kentucky House of Representatives from 1855 to 1859 and was later elected to the Kentucky Senate in 1877.

2. Battle of Bowling Green: On March 21, 1862, during the Civil War, Confederate and Union forces clashed in the Battle of Bowling Green, which took place near Bowling Green, Kentucky. The battle resulted in a Union victory and contributed to the collapse of Confederate control in western Kentucky.

3. Formation of the Kentucky Academy of Science: On March 21, 1914, the Kentucky Academy of Science was officially formed. The organization is dedicated to promoting scientific research and education in Kentucky and has been instrumental in advancing scientific knowledge in the state.

4. Prohibition Repealed in Kentucky: On March 21, 1933, Kentucky became the 21st state to ratify the 21st Amendment to the US Constitution, which repealed Prohibition. With the repeal of Prohibition, the production and sale of alcoholic beverages became legal in Kentucky once again.

5. Birth of John Snow, Jr.: John Snow, Jr., an African-American physician who made significant contributions to the field of anesthesiology, was born on March 21, 1920, in Bowling Green, Kentucky. Snow was the first African-American physician to serve as a resident at Massachusetts General Hospital and also helped establish the National Medical Association's Anesthesia Section.