The United States Navy, one of five national military branches, is responsible for the preparation and maintenance of maritime vessels and troops to be deployed in the defense of the United States and marine freedom.
Although an initial glance at the official Navy website does not suggest that the department offers educational materials, the site provides a wide variety of resources which could be put to good use in the history classroom. These include modern Navy photographs and both print and web advertisements for comparison to historical photographs, recruitment posters, and insignia within the Naval Heritage and History Command's Online Library. The library also presents Naval biographies and a selection of online reading, which includes Naval abbreviations and period regulations.
If you desire more information on 20th-century Naval life or action, a good starting point would be the archives of Naval Aviation News, with back issues from 1943 to present, or All Hands Magazine, with issues from 1922 to present day.
Other online resources include art exhibits, short essays related to Naval artifacts, and the Little Skippers page. The latter contains a lesson plan, latitude and longitude activity, and word search.
If you are looking for field trip opportunities, the Navy maintains the official National Museum of the United States Navy, which houses exhibits of U.S. Naval history, covering topics from polar exploration to military actions and navigation. The DC Naval Yard also holds the early history (1776-1919) and operational archives. Visitors unable to reach the Washington Naval Yard, may find the list of other official U.S. Naval museums useful.