"...tragedy: The ship onto which they flee with the
ugly inevitability of fate is the Wilhelm
Gustloff, which was sunk by a Soviet
submarine in January 1945. Of the estimated
10,500 people on board, more than 9,000
perished in the icy seas. We watch these..."
http://mobile.nytimes.com/2016/02/14/books/review/salt-to-the-sea-by-ruta-sepetys.html