1. Arizona became a territory: On March 15, 1864, President Abraham Lincoln signed the Organic Act, creating the Arizona Territory. This paved the way for the eventual statehood of Arizona in 1912.

2. Geronimo surrendered: On March 15, 1886, Geronimo, the famous Apache warrior, surrendered to U.S. Army General Nelson A. Miles near the Arizona-New Mexico border. This marked the end of the Apache Wars and the confinement of most Apaches to reservations.

3. Women gained suffrage: On March 15, 1912, Arizona became the tenth state to grant women the right to vote. This was eight years before the ratification of the 19th Amendment, which extended suffrage to women throughout the United States.

4. Meteor Crater formed: Approximately 50,000 years ago, a meteorite crashed into northern Arizona, creating what is now known as Meteor Crater. This giant hole in the ground, which is nearly one mile wide and 550 feet deep, is considered one of the best-preserved examples of a crater caused by a natural impact.

5. State Capitol building dedicated: On March 15, 1960, the Arizona State Capitol building was officially dedicated. This iconic structure, which is located in downtown Phoenix, has become an important symbol of Arizona's government and history. It features a dome made of copper and a rotunda adorned with murals depicting state history.