1. On June 28, 1914, the assassination of Archduke Franz Ferdinand and his wife Sophie took place in Sarajevo, Bosnia. This event would ultimately lead to the start of World War I, which greatly impacted Oklahoma and the rest of the world.

2. In 1927, the world's first airport weather service was established in Oklahoma City. This service provided pilots with important weather information for their flights, improving safety for all involved.

3. On June 28, 1942, the Women's Army Auxiliary Corps (WAAC) was established. This organization allowed women to serve in non-combat roles during World War II, and many Oklahomans joined the WAAC to support the war effort.

4. In 1969, Governor Dewey F. Bartlett declared a state of emergency due to severe flooding in several Oklahoma counties. This flooding caused significant damage to homes and businesses, and many people had to be evacuated from their homes.

5. On June 28, 2004, the Oklahoma state flag was changed to its current design. The flag had previously featured a Native American warrior and the state seal, but the new design features a larger and more prominent Native American image, as well as a blue background with a white star.