Coastal defense structures are built to protect shorelines from erosion, flooding, and storm surges. These structures include sea walls, breakwaters, and groins, which help to absorb wave energy and reduce the impact of water on the land. They are essential for safeguarding coastal communities and infrastructure. In addition to protecting land, coastal defense structures can also create habitats for marine life. For example, breakwaters can provide calm waters that encourage the growth of coral reefs and other aquatic ecosystems. Properly designed, these structures can balance human needs with environmental conservation.