1. On May 13, 1917, the first official Navajo Tribal Council meeting was held in Window Rock, Arizona. This marked an important milestone in Navajo history as it signaled the tribe's transition from a decentralized system of governance to a more centralized one.

2. The Arizona Diamondbacks played their first game on May 13, 1998, in Phoenix. The Diamondbacks beat the Colorado Rockies 9-2 in front of a sold-out crowd of 50,179 fans at Bank One Ballpark (now Chase Field).

3. May 13, 1966 marked the opening of the first McDonald's restaurant in Arizona. The restaurant was located in Phoenix and was the first of many fast-food chains that would soon pop up across the state.

4. On May 13, 2009, the town of Hillside, Arizona was hit by a devastating wildfire. The fire destroyed over 210 homes and burned over 15,000 acres of land in just a few days. It remains one of the worst wildfires in Arizona history.

5. In 1883, lawman and gunfighter Wyatt Earp was wounded during a shootout in Tombstone, Arizona. The shootout, famously known as the Gunfight at the O.K. Corral, occurred on October 26, 1881, but Earp's injuries persisted until May 13, 1883, when he was shot in the arm during an ambush in Tombstone.