1. On December 11, 1912, Arizona was officially admitted to the Union as the 48th state. It was the last of the contiguous states to be admitted, and its statehood marked the end of the era of western expansion in the United States.

2. In 1931, on December 11, the Hoover Dam was dedicated in a ceremony attended by President Herbert Hoover. The dam, which spans the Colorado River between Arizona and Nevada, was a major engineering feat of the time and provided hydroelectric power and water to the growing Southwest.

3. On December 11, 1967, the town of Carefree, Arizona was incorporated. The town, located in Maricopa County, was designed as a master-planned community with a focus on nature, art, and culture. It has since become a popular destination for tourists and retirees.

4. In 1985, on December 11, the Phoenix Coyotes hockey team played their first home game at the Arizona Veterans Memorial Coliseum. The team, which moved to Arizona from Winnipeg, Canada, became the first professional sports team in the state.

5. On December 11, 2017, the city of Phoenix approved a plan to build a new $150 million soccer stadium in the downtown area. The stadium, which will be home to the Phoenix Rising FC soccer team, is part of a larger effort to revitalize the city's urban core and attract more tourism to the area.