The Cook Islands, a sovereign state in free association with New Zealand, uses two official legal tender currencies. The New Zealand Dollar circulates in parallel with the local Cook Islands Dollar; at the same time, the government also authorises many legal tender coins in the Cook Islands Dollar currency for collector's purposes.
Collector coins are dedicated to historical or general popular culture themes not related to the country itself. Many of them are in standard bullion sizes, including the large three ounces of silver format - such as this coin.
The Nautilus is part of the Steampunk series by CIT Coin Invest.
The mint says about it:
With the yhird edition of the Steampunk series, we dive deep into the fantastic underwater world known from Jules Verne’s "20,000 Leagues Under the Sea". Having left the legendary Nautilus in deep-sea diving gear, we encounter giant sea snails, turtles, octopuses and shipwrecks. Of course, we also come across the series regular - the penny-farthing rider. | 
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