Here we are world ready to conclude this cryptic question we have all been pulling our hair out over: Why are manhole covers round? We last reviewed some probable and even rational reasons as to why they are round. Most sources stand by the functional theory in that a circle, in more ways then one, works better for the needs of people working with manholes. Some other less note-worthy remarks come in the form of manufacturing ease or efficiency. Better drainage in floods is also highly regarded as a contributor. All of these factors likely had some precedence in the design of the circular manhole covers. However, after all the evidence I still have a hypothesis that, while similar, differs from the norm.

As I the mentioned before, Microsoft has used this puzzling question to divide the on-the-spot thinkers from those who merely have book smarts. I read about 100 different replies posted on Yahoo! Answers as well as a blog sponsored by Forbes that highlighting the 10 most difficult interview questions. Out of all of these responses, evidence collected, and my own personal thoughts, only one think sung out with the song of truth, merit, and logic! Therefor I would like to construct the hypothesis that manhole covers are round because manholes themselves are in fact round.