The climax occurs when the battle at Bosworth Field goes badly. Richard's followers desert him. Richard has sought to rule by usurping the crown by seducing Lady Anne after claiming to have murdered her husband, and his glee in acting with evil intent seems to be repaid when his loss in battle is through a simple accident: he is unhorsed and put at a disadvantage, then slain by Richmond. ) When he utters the famous line "A horse! A horse! My kingdom for a horse!" Richard is referring to the fact that his kingship is lost because he fell off his horse, and in this way is cursing fate for treating him cruelly.
I feel that the climax is right after the procession of ghosts exits. Richard shows his first moment of vulnerability and insecurity. He identifies himself as a villain and realises that he has cut off every single relation that might have supported him. However, after this brief moment of understanding, Richard quickly dismisses his conscience and is back to the old Richard. This could have been a turning point for the character, hence, it becomes the climax. The audience hopes for a change, but is also aware that a change in heart would be inconsistent with Richard's character. He is too far gone to turn back and what is more, he does not want to turn back.
The moment also creates a lot of sympathy and pity within the audience, much of which had disappeared after his horrendous murders of even the most innocent (eg, the Princes). This is important in the context of the play, because the audience must respond to Richard's death and not rejoice.
Additionally, the recovery that Richard makes after his moment of weakness, that is his bravery on the battlefield, makes us admire him even more. Actions ▾