A maritime museum (sometimes nautical museum) is a museum specializing in the display of objects relating to ships and travel on large bodies of water. A subcategory of maritime museums are naval museums, which focus on navies and the military use of the sea. A recent activity of maritime museums is to build replicas of ships, since there are few survivors that have not already been restored and put on display. Another is operating a , most notably in Germany and the Netherlands but elsewhere too, that offers mooring to privately owned historical vessels, which can be watched but not boarded.