You see them on the streets of just about every city, but a KMPH viewer asks, "why are manhole covers round?"
It's one of those simple questions we all tend to take for granted, but do you know the answer?
To find out, we turned to the city of Fresno Public Works Director, Patrick Wiemiller, and he says, there is actually a very good reason why manhole covers are round.
"There is indeed," Wiemiller emphasized. "There are probably several reasons, but the main one is for a safety consideration. The round manhole cover cannot fall into the manhole whereas a square one would be able to if it was positioned correctly in the diagonal."
"You could pick it up and actually drop it down into the hole and so since they are quite heavy and people are working down below we wouldn't want that to happen, so the round one's hopefully prevent that from happening."
But, Wiemiller says, that's not the only reason.
"Those manholes are heavy so once they're lifted out of place you can move them around by rolling around one more easilyr than you can by lifting or dragging a square one."
Makes sense, doesn't it?
Now you know.
If you have one of those nagging questions for which you would like us to help you find an answer, include the title "Monty's Book Of Why," and send me your question.
You can e-mail it to email@example.com, or post it onto our KMPH Fox 26 Facebook page.
Our next question: "If the government needs to pay bills, does it just print more money?"
We'll have the answer Friday on Monty's Book Of Why on The KMPH Fox 26 Ten O'Clock News.