1. In 1837, the government officially opened the Chickasaw Nation for settlement. This led to a significant influx of settlers to the area, which eventually became the state of Oklahoma.

2. In 1892, the first transcontinental train arrived in Oklahoma City. This momentous event opened up the state to new opportunities for commerce and trade, helping it become the thriving economic center it is today.

3. In 1917, the first military airplane ever constructed in Oklahoma made its first flight. This event was a major milestone in the state's aviation history, helping it become a key player in the aerospace industry.

4. In 1964, a tornado struck the town of Fargo, Oklahoma, causing extensive damage and killing one person. This event was a stark reminder of the state's vulnerability to severe weather, and prompted renewed efforts to prepare for and respond to such disasters.

5. In 2018, it was announced that Oklahoma would become the first state in the country to use nitrogen gas as a method of execution. This controversial move sparked debate and criticism from many quarters, and remains a divisive topic in the state to this day.