1. In 1912, Arizona became the 48th state of the United States on February 14th. However, on February 13th of that year, President William H. Taft signed the proclamation declaring Arizona's statehood. Thus, February 13th can be considered the "official" date of Arizona's statehood.

2. On February 13, 1937, the Hoover Dam was officially completed, after five years of construction. The dam spans the Colorado River, between Arizona and Nevada, and is an engineering marvel and major tourist attraction.

3. In 1917, the first regularly scheduled airmail service in the world began in the United States, with a route that included Phoenix, Arizona. On February 13th of that year, the first airmail flight to Phoenix landed at the city's airport.

4. On February 13th, 1871, the Yuma Territorial Prison opened in Arizona. The prison was notorious for its harsh conditions and was known as the "Hellhole of the West." The prison operated until 1909 and is now a museum.

5. In 1991, on February 13th, the deadliest prison riot in United States history took place at the Arizona State Prison in Florence. The riot resulted in the deaths of 9 inmates and widespread destruction of the prison facilities. The riot was sparked by a feud between two rival gangs within the prison.