What is a caesura in poetry and what effect can it have?

A caesura is a pause in the middle of a line of poetry. It usually comes in the form of punctuation, and the most common ones are full stops and commas. A full stop creates a harsher contrast between the first and second part of the line. Look out for the use of colons, dashes, and semi-colons too. The effect of a caesura often depends on the tone and content of the individual poem, but it often has the effect of creating contrast, or providing a pause to allow the reader to take in the information presented in the first part of the line. It is often used after the description of something shocking or violent, to make the reader (or listener) pause and reflect on its shocking nature. Caesura can alter the rhythm of a line too, so it's worth reading it out loud to observe its effect on how the line sounds.