Despite their young age, children can have very profound thoughts - as one pupil has proved.
Teacher Bret Turner, from Albany, California, explained how one of his first-graders (aged 5 to 7) had given the philosophical answer "death" to his tricky puzzle of the week - causing an "awed, somber [and] reflective hush" to fall across the room, the Daily Mail reported.
The riddle read: "I am the beginning of everything, the end of everywhere. I'm the beginning of eternity, the end of time & space. What am I?"
Bret explained how the first guess from one of his pupils was "death", and others included "all stuff", "the end" and "nothingthing".
He said that when he finally revealed the correct answer - the letter e - the class of pupils were "largely unimpressed".