1. In 1964, a massive earthquake with a magnitude of 9.2 struck Alaska on September 17. This is known as the Great Alaska Earthquake and remains the most powerful earthquake ever recorded in North America. The earthquake caused massive destruction and triggered a tsunami that caused damage as far away as California.

2. The Russian American Company, which controlled Alaska for over a century, was officially dissolved on September 17, 1867. This cleared the way for the United States to purchase Alaska from Russia just seven months later.

3. September 17, 1955 saw the opening of the Trans-Alaska Pipeline System, a massive pipeline that stretches over 800 miles from the Arctic Ocean to the Gulf of Alaska. The pipeline enables crude oil to be transported from Alaska's North Slope to the Valdez terminal for shipment to refineries in the lower 48 states.

4. On September 17, 1912, the first telegraph line in Alaska was completed, connecting the territory with the continental United States. The telegraph line enabled faster communication between Alaska and the rest of the country, and was instrumental in the development of commerce and industry.

5. In 2015, President Barack Obama changed the name of Mount McKinley to Denali, the traditional name used by Alaska Natives for the mountain for thousands of years. The announcement was made on September 17, after years of lobbying by Alaska Native groups and politicians from the state.