There was actually a German U-boat in WWII with this number, but that is no reproduction. The number is based on the year 1856, when the Kulm Hotel opened its doors for the first time. The real U-856 was a 750-ton submarine commanded by Oberleutnant Friedrich Wittenberg. It sunk on 7 April 1944. Lake St.Moritz, Switzerland, Feb 12, 2014.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/70981241@N00">Kecko</a> from Switzerland (Rheintal SG)
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<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/kecko/12503836923/">St. Moritz U-856</a>