We’re talking about the sinking of the Lusitania, and the role that incident played in getting the U.S. into World War I.
Coincidence: Look at the date today.
Enlistment poster, after the sinking of the Lusitania
94 years ago today. U-20 sank the Lusitania, champion of the Cunard Line, on May 7, 1915.
World War I appears to have been a heyday for propaganda posters. Google up “Lusitania +poster” and you can find a wealth of recruiting posters and just plain propaganda posters. If only we had the time, there are a couple of lesson plans waiting in that search.
Note: Details on the poster: Artist, Fred Spear, 1915; “Enlist,” published by Sackett & Wilhelms Corp.
Other resources:
Posted by Ed Darrell 
Millard Fillmore's Bathtub 