1. In 1901, the first-ever automobile race in Arizona took place on July 17th. The race covered a distance of 38 miles between Phoenix and Tempe, and it was won by a man named George Green.

2. On July 17, 1911, the famous construction company, Morrison-Knudsen, was founded in Boise, Idaho. The company would go on to play a major role in the construction of the Hoover Dam, which was built on the border between Arizona and Nevada.

3. In 1931, the first-ever radio broadcast of a baseball game took place in Arizona on July 17th. The game was between the Phoenix Senators and the Tucson Cowboys, and it was broadcast on KAZ radio.

4. On July 17, 1955, Disneyland, the popular amusement park located in Anaheim, California, opened its doors to the public. Many Arizonans would make the trip to Disneyland during the summer to escape the hot Arizona weather.

5. Finally, on July 17, 1981, the Arizona Diamondbacks baseball team played their first-ever game. The Diamondbacks defeated the Sydney Blues, a team from Australia, in an exhibition game played at Hi Corbett Field in Tucson.