I much prefer swimming when there's a lifeguard on duty to supervise the safety of swimmers.
Definitely.  Pools and Oceans are places where medical attention and rescue efforts have to be given quickly.
Lifeguard
A lifeguard is a rescuer who supervises the safety and rescue of swimmers, surfers, and other water sports participants such as in a swimming pool, water park, spa, beach or river. Lifeguards are strong swimmers and trained in CPR/AED first aid, certified in water rescue using a variety of aids and equipment depending on requirements of their particular venue. In some areas, lifeguards are part of the emergency services system to incidents and in some communities,lifeguards may function as the primary EMS provider.
Lifeguard tower
Lifeguard towers are used at recreational beaches or public swimming pools to watch and supervise swimmers in order to prevent drownings and other dangers. Lifeguards scan for trouble from the structures, which vary from beach bungalows by the ocean to poolside towers. Lifeguard towers are also used to spot sharks and other threats.
The towers have featured in television shows including "Baywatch". Their construction is sometimes paid for with fundraisers, and their operation and staffing is subject to funding availability. Design contests have challenged architects to offer