Port Royale 2/Artifacts
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In the game, you may see a chest with a question Mark, this means that there is a quest item inside, sometimes it is an artifact, when you collect all 20 Artifacts and show them to your wife; you'll get a prize, a steam powered ship.
The Bonus Ship is one of the best ships in the game, it's very powerful, has a high maneuverability and a lot of cannons.