1. In 1874, the first train arrived in Tucson, Arizona, marking an important milestone in the city's transportation history. The train brought goods and passengers from cities such as San Francisco and Los Angeles, helping to boost Tucson's economy and population.

2. In 1883, the University of Arizona was established in Tucson, making it one of the oldest universities in the state. The university has a rich history in Arizona, and has been instrumental in shaping the state's education system and producing notable alumni.

3. In 1926, the iconic Route 66 was established in Arizona, running through the towns of Holbrook, Winslow, Flagstaff, Williams, and Kingman. The road connected the eastern and western coasts of the United States, and played an important role in the development of the American automobile industry.

4. In 1975, the stunning Glen Canyon Dam was completed in northern Arizona, creating Lake Powell, one of the largest man-made lakes in the world. The dam and lake have become popular tourist attractions in Arizona, drawing millions of visitors each year.

5. In 2014, a magnitude-7.1 earthquake struck near Sedona, Arizona, causing widespread damage and disruption across the region. While there were no fatalities, the earthquake was one of the largest to hit Arizona in recent history, and served as a reminder of the state's vulnerability to seismic activity.