Just for clarity (for anyone that does't know). 'crescendo' is a musical term that means grow louder. The opposite is 'diminuendo'.

In a music score a cresendo in the music is shown by a < under the music streching out as long as it is intended for the music to continue getting louder.

A common mistake is to say 'the music reached a crescendo' when what is meant is that the music reached some sort of climax. The 'reaching' is the crescendo, not where it ends up.