1. On August 3, 1912, the City of Phoenix officially opened its first municipal pool. The pool, located at East Lincoln and South Fourth streets, was constructed with funds raised from local businesses and citizens. It quickly became a popular summer destination for Phoenix residents and remained in operation until the 1950s.

2. August 3, 1929, marked the opening day of the Hoover Dam construction site. The dam, which straddles the Arizona-Nevada border on the Colorado River, took five years to build and was one of the largest public works projects in American history. The dam provided electricity and water to millions of people, and became a symbol of American ingenuity and progress.

3. The Arizona Diamondbacks played their first game at Bank One Ballpark on August 3, 1998. The team, which had been awarded to Phoenix four years earlier, defeated the Colorado Rockies in their inaugural game at the new stadium. Bank One Ballpark, now known as Chase Field, has been the Diamondbacks' home ever since.

4. On August 3, 1949, the Navajo Nation was officially recognized as a sovereign government by the United States government. The Navajo Nation, which covers more than 27,000 square miles in Arizona, New Mexico, and Utah, is the largest Native American reservation in the country. Today, the Navajo Nation has its own government and court system, and is home to more than 300,000 people.

5. August 3, 1964, was the day that President Lyndon B. Johnson signed the Gulf of Tonkin Resolution into law. The resolution, which was passed in response to an alleged attack on two American destroyers in the Gulf of Tonkin off the coast of Vietnam, gave the president broad powers to use military force in Southeast Asia. The resolution became the legal basis for the escalation of the Vietnam War, which would drag on for more than a decade and claim the lives of more than 58,000 Americans.