Internesting history of the Washington-Moscow hotline.  From the submarine cable perspective, one of the routes was a transatlantic cable that also passed terrestrially through the Nordic countries.  In the 1960s, the segment through Finland was cut by a farmer ploughing his fields.  Guess they weren't thinking about cable protection back then.  You can read the article at http://www.army.mil/article/109986/Hotline__now_50_years_old__continues_to_promote_dialog_with_Russians/.