1. On March 21, 1965, civil rights marchers began their historic protest from Selma, Alabama to the state capitol in Montgomery, Alabama. This march, known as "Bloody Sunday," was a crucial moment in the civil rights movement and galvanized support for voting rights for African Americans.

2. In 1879, the town of Ft. Meade was incorporated on March 21. Located in Polk County, this town has a rich history as a major center for cattle ranching and phosphate mining.

3. On March 21, 1935, construction began on the Overseas Highway in the Florida Keys. This highway, which was completed in 1938, connected the Keys to mainland Florida and was a major engineering feat of its time.

4. In 1999, NASA astronaut Tracy Caldwell-Dyson was born on March 21 in Arcadia, Florida. She went on to become the 174th person to board the International Space Station and spent over six months in space conducting scientific experiments.

5. On March 21, 1918, German U-boats sank three American ships off the coast of Florida, killing over 200 people. This incident, known as the 1918 Gulf of Mexico hurricane, was the only time during World War I that American vessels were sunk by German submarines in American waters.