1. On July 21, 1879, the USS Jamestown arrived in Sitka, Alaska, carrying the first shipment of telegraph wire used to construct a telegraph line across Alaska. This marked the beginning of modern communications in the state.

2. July 21, 1958, is known as "Statehood Day" in Alaska, as it was the date when President Dwight D. Eisenhower signed the Alaska Statehood Act into law, making Alaska the 49th state of the United States.

3. In 1943, on July 21, a Japanese ship carrying prisoners of war was bombed by American aircraft off the coast of Kiska Island in the Aleutian Islands. This incident resulted in the deaths of over 300 Japanese soldiers and prisoners.

4. On July 21, 1952, Alaska Airlines Flight 4 crashed into a mountain near Mount Sanford, killing all 52 passengers and crew on board. The cause of the crash was determined to be pilot error, and it remains one of the deadliest aviation accidents in Alaska's history.

5. In 1960, on July 21, a 7.8 magnitude earthquake struck the Aleutian Islands, causing a tsunami that devastated coastal communities throughout the region. The tsunami reached heights of up to 30 feet and resulted in several fatalities and extensive damage to infrastructure.