Why are manholes circular?

Question

Accepted Answer

Manholes are circular because they cannot fall through their own opening.

Circular manholes cannot fall through their own opening, unlike square or rectangular ones.
Circular shape distributes weight evenly, making it easier to move and handle.
Circular shape also reduces the risk of injury from sharp corners.
Circular manholes are easier to manufacture and install.
Circular shape allows for easier access from any angle.
Circular manholes have been used for centuries, dating back to ancient Rome.
Other shapes have been used in the past, but circular has become the standard.
Some countries have experimented with other shapes, such as triangular or hexagonal.
However, circular manholes remain the most common and practical choice.

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