1. On May 21, 1895, the state of Oklahoma experienced one of its deadliest tornadoes. The tornado hit the town of Chelsea, Oklahoma, and killed 71 people, injuring many others. This tragedy is remembered as one of the worst tornado disasters in state history.

2. May 21, 1919 marks the date that the first commercial flight from Chicago to Los Angeles landed in Oklahoma City. The trip was made by the airline Transcontinental Air Transport (TAT) and would revolutionize air travel in America, leading to the establishment of the modern airline industry.

3. One of the most significant events in Oklahoma history occurred on May 21, 1958 when Congress passed the Indian Claims Commission Act. This Act established the Indian Claims Commission as a legal body responsible for adjudicating tribal claims against the US government, ultimately leading to the payment of billions of dollars in compensation to tribes throughout the country.

4. On May 21, 1970, Oklahoma's women gained the right to serve on juries for the first time in state history. This was a significant step forward for women's rights in the state and was celebrated as a victory for gender equality.

5. On May 21, 2006, Oklahoma City hosted the 50th Anniversary of the National Cowboy & Western Heritage Museum. This event brought together cowboys, historians, and enthusiasts from across the country to celebrate the legacy of the American West and its continued influence on Oklahoma culture.