1. Oklahoma experienced a large earthquake on March 20, 2011. The magnitude-4.7 earthquake was felt across the state, and caused damage to buildings in Oklahoma City.

2. The Oklahoma Legislature officially designated the Oklahoma state rock, rose rock, on March 20, 1968. The rock is a type of barite that forms in a unique shape resembling a rose.

3. On March 20, 1893, the University of Oklahoma was established by an act of the Oklahoma Territorial Legislature. The university would later become one of the largest and most respected universities in the state.

4. March 20, 1952, saw a major outbreak of tornadoes across Oklahoma. The largest of these tornadoes hit the town of Tishomingo, killing two people and causing extensive damage.

5. The Osage Nation declared March 20th as “Osage Nation Day” in honor of their constitution, which was signed on that date in 2006. The constitution outlines the rights of the Osage people and establishes the structure of their tribal government.