For series TV fans, “The Crown” is a drama based on the life of Queen Elizabeth II.   “The Americans” (seasons 1-3) tells about two KGB officers posing as an American couple during the late years of the Cold War.   Their kids have no idea what their parents are up to.  Fans of “Homeland” will want to see this one. “Poldark 3” continues the travails and adventures of scorned Englishman Ross Poldark, who lost his lands and loves while fighting for the crown.  “Vikings” (seasons 1-3) skillfully blends myth and history.  At the center is the mythic Ragnar Lothbrok, warrior and navigator, who famously led raids on England.  His story, drawn from Norse sagas, is intertwined with real events, such as Viking raids on Lindisfarne (England) and Paris. Think “Game of Thrones” meets the Lesser Edda, minus dragons.