Coast defense refers to military strategies and systems designed to protect a nation's coastline from naval attacks and invasions. This includes the use of fortifications, coastal artillery, and surveillance systems to monitor and respond to threats. The goal is to secure vital ports and coastal areas, ensuring the safety of maritime trade and national security. Historically, coast defense has involved various technologies and tactics, such as the construction of forts, batteries, and minefields. Countries often invest in coast defense to deter potential aggressors and maintain control over their territorial waters, which are crucial for economic and strategic interests.