A "Sea Fortress" is a type of military structure built on or near the water, designed to protect coastal areas from naval attacks. These fortifications often include walls, towers, and other defensive features, allowing them to withstand bombardment and provide a strategic advantage in maritime warfare. Historically, sea fortresses were crucial during conflicts, serving as bases for naval operations and as safe havens for ships. Notable examples include the Fortress of Louisbourg in Canada and the Dover Castle in England, which played significant roles in their respective regions' defense strategies.