1) The smallest unit of time is known as a zeptosecond, which is equal to one trillionth of one billionth of a second.

2) The first graphical web browser, Mosaic, was released in 1993 and played a key role in popularizing the World Wide Web.

3) The highest-grossing film of all time is "Avengers: Endgame," which has earned over $2.79 billion at the global box office.

4) The world's first car radio was invented in 1929.