1. In 1860, the Arizona Territory was established. Prior to this, the land that is now Arizona was part of New Mexico Territory.

2. In 1882, the first train arrived in Tucson, marking a major milestone in the growth of the city and the expansion of transportation in Arizona.

3. In 1924, Arizona Governor George W. P. Hunt signed a law that granted citizenship to Native Americans born in Arizona. This was an important step towards recognizing the rights of Indigenous peoples in the state.

4. In 1948, the first night game was played at Hi Corbett Field in Tucson. This stadium was home to the Tucson Toros, a minor league baseball team.

5. In 1971, the first Earth Day was celebrated in Arizona and across the country. This event helped to raise awareness about environmental issues and sparked a movement towards greater conservation and sustainability.