1. In 1952, a deadly tornado struck the town of Harvard, Nebraska, killing 4 people and injuring dozens more. The tornado was part of a larger outbreak that swept across the Great Plains that day.

2. In 1944, the first atomic bomb was successfully detonated at the Alamogordo Bombing Range in New Mexico. This event marked a major milestone in the development of nuclear weapons, which played a significant role in the Cold War.

3. On July 6, 1923, the first transcontinental airmail service was inaugurated, as pilots flew the mail from New York to San Francisco. The service significantly reduced delivery times for mail and helped to spur the growth of commercial aviation in the United States.

4. In 1917, Nebraska became the first state in the country to adopt a unicameral legislature, in which all legislative power is vested in a single chamber. The unicameral system has been praised for its efficiency and effectiveness in passing legislation.

5. In 1867, the construction of the Union Pacific Railroad was completed, linking the east and west coasts of the United States for the first time. The railroad was a major factor in the expansion and growth of Nebraska and the West, but also had a significant impact on the displacement of Native American communities.