A foreshadowing of things to come in America...
General George McClellan was a Captain during the Crimean War and was a military observer. I had remembered that some Civil War notables had been there, and that’s what I found.
See item 3 here, for instance:
http://history1800s.about.com/od/europeanwars/fl/Five-Facts-About-the-Crimean-War.htm