Elizabeth Castle is a castle and tourist attraction, on a tidal island within the parish of Saint Helier, Jersey. Construction was started in the 16th century when the power of cannon meant that the existing stronghold at Mont Orgueil was insufficient to defend the Island and the port of St. Helier was vulnerable to attack by ships armed with cannon.
It is named after Elizabeth I who was the queen of England around the time the castle was built.
Wikipedia https://en.wikipedia.org/wiki/Elizabeth_Castle
Official Website https://www.jerseyheritage.org/places-to-visit/elizabeth-castle
Coordinates 49°10'36.456" N -2°7'30.493" E
