Misahuallí’s most enjoyable sight is some way outside the town, but it’s well worth spending a few hours to do the return riverside walk, which takes you through the rainforest. Take a Misahuallí–Puerto Napo bus and ask the driver to drop you at el camino a las cascadas (the trail to the falls) about 15 minutes from Misahuallí.
All the drivers know it, and you can't miss the big sign on the side of the road. Follow the river upstream to the falls, which takes an hour, passing several swimming holes en route. Be prepared to wade.