It is believed that a vast treasure was hidden on Cocos Island (https://www.detecting.org.uk/html/Treasure_of_Cocos_Island.html)in 1821 by the mutinous crew of the Mary Dear (or Mary Deare, depending on source), a British ship chartered to move gold, silver and jewels from the churches of Lima, Peru to the safety of Spain.
Full story here:
https://www.detecting.org.uk/html/Treasure_of_Cocos_Island.html