1. Cinco de Mayo: May 5 is widely celebrated as Cinco de Mayo which commemorates the Mexican army's victory over French forces in the Battle of Puebla on May 5, 1862. Many Oklahomans celebrate the day with parades, music, and traditional Mexican food and drinks.

2. Tornado outbreak: On May 5, 1960, one of Oklahoma's worst tornado outbreaks occurred when multiple tornadoes tore through several towns in the northern part of the state. In total, 76 people were killed and over 1,000 were injured.

3. Oklahoma City bombing: May 5 marks an important day in the investigation into the Oklahoma City bombing. On this day in 1995, Timothy McVeigh rented a truck that he would later use to detonate a bomb outside the Alfred P. Murrah Federal Building, killing 168 people.

4. Statehood anniversary: Oklahoma became the 46th state in the United States on November 16, 1907. However, the date that Oklahoma celebrates its statehood is May 5, which is known as Statehood Day.

5. Black Wall Street massacre: On May 31 and June 1, 1921, a horrific massacre took place in Tulsa's Greenwood district, which was known as Black Wall Street. It started after a young Black man was accused of assaulting a white woman and ended with the destruction of the community and the loss of countless lives. May 5 is significant because it was the day that a white mob had gathered outside of the courthouse to lynch the accused man before he was relocated, sparking the deadly riots.