Churchill promoted "" in 1940 and again in 1944 where floating mines were put into the in France to float down the river, becoming active after a time calculated to be long enough to reach German territory.
Mine-clearance dolphins were deployed in the during the in 2003.
In March 1945, began in earnest, using 160 of LeMay's B-29 Superfortress bombers to attack Japan's inner zone.
Parts of some naval minefields still exist because they are too extensive and expensive to clear.
The Development of Mine Warfare: A Most Murderous and Barbarous Conduct.
The first plan for a sea mine in the West was by Ralph Rabbards, who presented his design to Queen in 1574.