Jersey is a popular vacation destination, for its mild climate, long beaches washed by Gulf Stream waters, and unusual hybrid "franglais" culture. How this little bit of France became a Crown Dependency of the British monarch is a fluke of history.
The Duchy of NormandyThe Channel Islands were a part of the Duchy of Normandy and among the possessions William the Conqueror brought with him when he became King of England in 1066. For about two hundred years, the islands, along with Normandy and England, were united but the islands were administered from Normandy. In 1204, King John of England lost Normandy to the King of France. To keep the loyalty of the strategically important Channel Islands, he decreed they could continue to be governed according to the laws they were used to - Norman law.
As a result, a separate system of government was created with the British Monarch ruling as the "Duke of Normandy". Although the systems have changed over time, Jersey retains its separate-ish status. It is not part of the EU - though it has an associate relationship to facilitate trade. It is not subject to the laws of the UK Parliament, though UK currency is legal tender and it depends upon the UK armed forces for defence. The official languages are English and French and there is a local patois that blends them both.
Oh, and one last oddity - to islanders, Queen Elizabeth II is still considered the Duke of Normandy and referred to, by the island legislature, as "Our Duke".
Jersey's main town is St. Helier.