Blackrock Castle in Cork city, Ireland [3 pictures]

Blackrock Castle formerly Mahon Castle, is a 16th century castle located in Cork city, Ireland. In the late 16th century, the citizens of Cork appealed to Queen Elizabeth I to construct a fort at Blackrock to "repel pirates and other invaders". In or around 1600, a round tower was constructed to safeguard against pirates "carrying away" vessels entering the harbour. [sources 1, 2]