You can pay to visit this site and see the original cave pool as well as various displays, some of which are media-driven. However, in today's information age, you can learn much of this information on the Internet. There is a nice (and free) boardwalk (with numerous stairs leading up the side of the mountain) which takes you up to some hot springs/snail sights and provides views of the exterior pool, set up as it was in the early years; there are many interpretive signs which help explain the history. If you wish to save some money just do the walk; it starts to the left of the stairs leading to the Cave & Basin NHS.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.