1. On April 12, 1945, Franklin D. Roosevelt died at his home in Warm Springs, Georgia. Roosevelt played a significant role in Oklahoma history, particularly during the Dust Bowl era, where he implemented policies and programs to address the devastating effects of the environmental crisis on Oklahoma farmers.

2. On April 12, 1993, a massive explosion occurred at the Alfred P. Murrah Federal Building in Oklahoma City. The attack, carried out by domestic terrorists, killed 168 people and injured hundreds more. The tragedy remains one of the deadliest acts of domestic terrorism in US history.

3. On April 12, 1893, the University of Oklahoma was established by territorial legislation. Today, the university is one of the largest in the state and a prominent public research institution.

4. On April 12, 1971, Tulsa hosted the first-ever National Indian Youth Council (NIYC) Conference. The NIYC was a prominent Native American advocacy group, and the conference attracted hundreds of young activists from around the country to discuss issues affecting Native American communities.

5. On April 12, 1963, Carl Albert was elected Speaker of the US House of Representatives. Albert, a native of McAlester, Oklahoma, served as Speaker from 1971 to 1977 and played a significant role in shaping national policy during a tumultuous period in US history.