An aircraft recognition thread because that was a long established hobby and I used to be (and still am) fairly good in that dept.
But in this day of Google earth and images taken by everyone I think a ship and sub recognition thread would be useful. First there is a question of recognition and nationality. Then an identification of type of ship and role and finally systems on board.
Unfortunately I am not skilled enough to make ten informative posts to get the thread going - but I will start with one and hope fully others can add gyan or doubts.

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