1) The word "piano" contains three vowels: I, A, and O.

2) 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.

3) The highest-grossing concert tour of all time is U2's "360° Tour," which earned over $735 million in ticket sales.

4) The Black Lives Matter movement gained renewed momentum in 2020 following the killings of George Floyd, Breonna Taylor, and others, sparking protests and discussions on systemic racism, police reform, and social justice around the world.