1) 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.

2) The word "pizza" contains two vowels: I and A.

3) The speed of light is approximately 299,792,458 meters per second.

4) The Berlin Conference in 1884-1885 divided Africa among European powers and set the stage for the colonization of the continent.