1. In 1909, the Arizona Legislature enacted a law establishing the Arizona State Normal School in Flagstaff, now known as Northern Arizona University. The school's purpose was to train teachers for Arizona's public schools.

2. In 1910, Arizona's first statewide primaries were held on May 3. The primary elections were part of the state's first direct primary law, which allowed registered party members to choose their candidates for office.

3. May 3, 1942, marked the establishment of the Luke Air Force Base in Glendale, Arizona. Named after Lieutenant Frank Luke Jr., a World War I Medal of Honor recipient, the base has been a prominent training center for fighter pilots from the U.S. Air Force and foreign military units.

4. On May 3, 1962, Arizona State University held its first graduation ceremony in Sun Devil Stadium. More than 1,000 students received degrees and diplomas in the university's first official graduation ceremony.

5. In 2003, May 3 was declared "Arizona Day of Prayer" by Governor Janet Napolitano. The day was intended to encourage Arizonans of all faiths to come together and pray for the state's well-being.