Nauyaca waterfall and horseback riding tour is reported to be the number one tourism activity in the Dominical area. I'm not sure how those numbers could be established, but from just looking around and being here in the area for a number of years, I'd say that there is a good chance that it is true. It is certainly one of the best value's in a Costa Rica adventure tour that you can get.
You start at 8:00 in the AM and get back to the main road at between 2:00 & 3:00. You are fed breakfast & lunch by the most gracious hostesses & host on the planet. You get to see a stunningly gorgeous Costa Rica waterfall. For the adventurous ones you can swim in the water at the base of the falls and dive off of the rocks.