Old minefields are areas where a minefield was once located in a past war or conflict. There may still be mines at these sites, either still active or no longer functional. Old minefields are likely found at sites of old battlefields or old borders. If these minefields are underwater minefields, they may be in treacherous waters or encircling harbors or other sites that at one time were of strategic value. Old minefields are common elements in worlds that take place in a post-war era.