1) The Cuban Missile Crisis in 1962 brought the United States and the Soviet Union to the brink of nuclear war during the Cold War.

2) The Hubble Space Telescope, launched in 1990, has provided breathtaking images of distant galaxies and deep space.

3) Bats are the only mammals capable of sustained flight.

4) The first successful mass-produced personal computer, the IBM PC, was introduced in 1981 and played a significant role in popularizing the use of computers in homes and offices.