This question revolves around an individual's own perception when considering Macbeth and its climax. It depends whether you think the climax is
- Duncan's murder which reinforces Macbeth's "vaulting ambition."
- Macbeth's rise to so-called greatness and his realization that Banquo's sons would succeed him not his own thus leading him to more and worse crimes:
"No son of mine succeeding...For them the gracious Duncan have I murder'd..." (III. i. 63- 65)
- The contribution of the witches and the supernatural in turning the real world into an unnatural world where reality and evil become interchangeable - "fair is foul and foul is fair." The declining sanity
in the paranoid hallucinations and, most markedly, in the insomnia of Macbeth and of Lady Macbeth.
4. The psychological effect on Lady Macbeth when she has lost her control over Macbeth and longs for that role to resume; ironically as she previously wanted, by her own admittance, to be "de-sexed." She is ony capable of nurturing Macbeth.
"give me your hand … to bed, to bed, to bed" (V.i.66-68).
5. Macbeth's own demise when he is killed by a man not "of woman born."
For me, the climax must come when Macbeth realizes that
"it is a tale
Told by an idiot, full of sound and fury,
Signifying nothing."(V. v. 26-28)