Boxing requires all kinds of athletic ability.
Having natural gifts like strength, speed and quickness definitely help any boxer, but they are not enough.
A strong man may look like he should punch hard when he is in the ring, but that's just one of the factors that goes into delivering a powerful shot to your opponent.
Factors like timing, balance, aggressiveness and anticipation all go into a boxer's punching ability.
Manny Pacquiao snaps off his jab with power and purpose and he does not have a bodybuilder's physique or weightlifting ability. However, his jab is thrown with such perfect timing that it can stun an opponent and send him reeling.
Here are five of the best punches in boxing history and the fighters who threw them.