Phoenix, Arizona

1911Roosevelt Dam Completed: The first major federal reclamation project provided reliable water and electricity to the Phoenix area, transforming the desert valley into productive farmland and enabling the city's future growth.

1950Air Conditioning Boom Transforms Phoenix: The widespread adoption of affordable refrigerated air conditioning in the 1950s made Phoenix livable year-round, triggering one of the most dramatic population explosions in American urban history.

1912Arizona Achieves Statehood: Arizona became the 48th state on February 14, 1912, with Phoenix as its capital. Statehood brought federal investment and political representation that accelerated the city's development.

1942Japanese American Internment Camps: Over 13,000 Japanese Americans were forcibly relocated to internment camps in the Arizona desert during World War II, including camps near Phoenix. The internment remains one of the darkest chapters in the region's history.

1981Sandra Day O'Connor Nominated to Supreme Court: Phoenix-area judge Sandra Day O'Connor became the first woman nominated to the U.S. Supreme Court, a landmark moment in American judicial history with deep roots in Arizona politics.

1991Charles Keating Savings and Loan Scandal: The collapse of Lincoln Savings and Loan, headquartered in Phoenix, became the centerpiece of the nationwide S&L crisis. The scandal cost taxpayers $3.4 billion and sent Keating to prison.

2010SB 1070 Immigration Law: Arizona passed the nation's strictest anti-illegal immigration law, requiring police to check immigration status during stops. The law sparked nationwide protests and a Supreme Court challenge.

1968Phoenix Union High School Walkouts: Mexican-American students walked out of Phoenix Union High School to protest discrimination and inadequate education, part of the broader Chicano civil rights movement sweeping the Southwest.

2020Phoenix Becomes 5th Largest U.S. City: The 2020 Census confirmed Phoenix had surpassed Philadelphia in population, reaching 1.6 million residents and cementing its position as a major American metropolis.

1930Rise as Tuberculosis Treatment Center: Phoenix's dry desert climate attracted thousands of tuberculosis patients and health seekers, driving the city's early population boom and establishing its first hospitals and medical infrastructure.