With its combination of Caribbean history, Spanish influence and US government ties, Puerto Rico is a place that feels both familiar and foreign.  Megan takes in the stunning scenery - beaches, natural reserves and the charming locals, before heading to Arecibo Observatory, home of the world's largest radio telescope where she names an asteroid and asks an alien expert the question we all want to know:  Is there anyone else out there?  Afterward, she continues to the Dominican Republic in search of a mode of transport where she meets a character who comes to define the last chapter of Sea Nation.