Llanos de Cortez waterfall: 

Located 60 km from the hotel, around 58 min by car. It is a big waterfall where you can swim under, relax on the sandy area, and/or hike to the top for a view of the fall. It is the perfect jungle day trip. There isn’t any place to buy things in the area, so it is best to bring everything that you may need. Bring some cash to pay for a “National Parks & Protected Areas” entry fee.  

Google maps:  Directions Link