1. On October 15, 1916, the Roosevelt Dam was officially dedicated by then-President Woodrow Wilson. The dam, located in Tonto National Forest, is still in operation today and provides water and hydroelectric power to the region.

2. In 1969, the first Tucson Meet Yourself festival was held on October 15. This festival celebrates the cultural diversity of Tucson and features music, dance, and traditional food from various ethnic groups.

3. On October 15, 1974, Arizona State University officially dedicated the Hayden Library. The library, named after former Arizona Senator Carl T. Hayden, is one of the largest academic libraries in the United States.

4. In 1980, the first Wildlife World Zoo and Aquarium opened in Litchfield Park, Arizona on October 15. Today, the zoo and aquarium is home to over 600 species of animals and is a popular tourist destination in the state.

5. On October 15, 1991, the Phoenix Suns retired the jersey of former guard Paul Westphal. Westphal played for the Suns from 1975-1980 and was a five-time NBA All-Star during his career.