1) The first photograph of a black hole was captured in 2019 using a network of telescopes around the world.

2) The American Civil Rights Movement, led by figures like Martin Luther King Jr., fought for equal rights and helped bring about significant social and legislative changes.

3) In Aztec mythology, Quetzalcoatl is a prominent deity often depicted as a feathered serpent. He is associated with creation, fertility, and wind, and is considered a cultural hero and patron of priests and rulers. The arrival of Spanish conquistadors was interpreted by some as the return of Quetzalcoatl.

4) The concept of 3D printing, also known as additive manufacturing, was first introduced in the 1980s and has since revolutionized prototyping and small-scale production.