The information provided by maps can be amazingly powerful. In 1680 the captain of the Spanish ship the Rosario, threw his valuable collection of maps into the sea. You may ask why any sane sea captain would do such a thing?
The Captain’s maps showed the Pacific coast of Central and Southern America, and included details previously unknown to the English. The Rosario had been captured by an English ship, and the Captain believed it was better to destroy the maps than to allow the English to obtain such valuable information. But the English managed to recover the maps, and to return them safely to London. This map of the west coast of South America is by William Hack. It is one of a series of maps copied from those saved by the English ship.