The Río Santo Domingo is a beautiful, turquoise mess of cascades and rapids. Some of the river pools are great swimming spots; it’s M$20 per person to swim here if you’re not staying the night. A swinging bridge straddles a fierce section of water-carved canyon, making an excellent vantage point from which to swoon over the grandest waterfalls. There’s also an adrenaline-pumping zip-line (M$150), and you can spelunk and rappel from February through June.
There are some enjoyable walking opportunities along the riverbank and into the forest. The most popular short walk is the 15-minute amble up to a mirador where you will be rewarded with blue-green jungle views. The bird watching all around here is great. Activities are paid for through Las Nubes.