1. On July 20, 1917, the United States Army established Fort Richardson near Anchorage, Alaska. The fort played a crucial role in the defense of Alaska during World War II and now serves as a major military installation for the United States Army.

2. In 1977, on July 20, three hikers made a discovery that would change the course of human history: the remains of a 25-year-old woman who lived over 9,000 years ago in what is now known as the Upward Sun River site in eastern Alaska. The discovery provided important insights into the early human settlement of the Americas.

3. On July 20, 1982, the Alaska State Flag was officially adopted. Designed by 13-year-old Benny Benson in 1927, the flag features eight gold stars representing the Big Dipper and North Star on a dark blue background, symbolizing Alaska's eternal northern sky.

4. In 2006, on July 20, Mount Augustine, a volcano located on an island in Cook Inlet, erupted for the first time in over 20 years. The ash plume from the eruption reached over 35,000 feet, causing disruption to air travel and leading to a state of emergency being declared.

5. On July 20, 2017, after 30 years of litigation, the Exxon Valdez Oil Spill Trustee Council announced that the remaining $100 million in damages from the 1989 Exxon Valdez oil spill would be distributed to the affected local communities in Alaska. The spill, which resulted in the release of over 10 million gallons of crude oil into Prince William Sound, had a devastating impact on the environment and local communities.