Whenever I see footage of divers, free falling off a cliff into an deep ocean inlet, I empathize the sensation of danger they are facing. This prompted a question in my mind, that applies to both physics and biology. If the water is plenty deep and there are no obstructions between the cliff and the water, what is the maximum height a person can make a free dive without incurring physical injury? This could be broken down into degrees. The range could include: pain, bruising, soft-tissue damage (brain damage), broken bones, death. Here is an example outside the limit: Un unobstructed free-fall dive into deep water of 66m (217ft) is lethal. After viewing your thoughts, I will outline some assumptions.