1. Battle of San Jacinto: On March 21, 1836, Texan forces under the leadership of General Sam Houston launched a surprise attack on the Mexican army, resulting in a decisive victory that effectively ended the Texas Revolution. The Battle of San Jacinto remains one of the most significant events in Texas history, and the date is now celebrated as San Jacinto Day.

2. First Telephone Exchange: On March 21, 1878, the first telephone exchange in Texas was established in Galveston by the Southwestern Telegraph and Telephone Company. This marked a major milestone in the development of telecommunications in Texas and paved the way for the widespread adoption of telephones throughout the state.

3. First Women’s Air Derby: On March 21, 1929, the first Women's Air Derby took off from Santa Monica, California, with a scheduled stop in Fort Worth, Texas. The derby, also known as the Powder Puff Derby, was a pioneering event in women's aviation and attracted some of the most accomplished female pilots of the era.

4. Civil Rights Demonstrations: On March 21, 1960, a group of African American students from Texas Southern University staged a sit-in at a whites-only lunch counter in a Houston department store. This marked the beginning of a series of civil rights demonstrations in Houston and other Texas cities that helped to lay the groundwork for the broader movement for equality and justice.

5. Texas Independence Day Parade: While not technically on March 21 itself, the Texas Independence Day Parade is traditionally held in the days leading up to March 21 in the city of Austin. This festive celebration of Texas history and culture includes marching bands, historic reenactments, and colorful floats, and draws participants from across the state.