Dover Harbour is where the Germans would have landed in 1940, and Dover Castle commanded the heights with lots of artillery. It would have been a costly operation, given that there were artillery emplacements in the harbor's breakwater as the first line of defense. The British even developed floating pools of burning oil to repel the Germans if they invaded. The 25-pounder guns of Dover Castle had the range to rain fire down on the Nazis as they landed. The Harbour's breakwater also had 6-inch guns mounted in 1908 in the 19th-Century Admiralty Pier Turret. Additional coastal guns were mounted in the Harbour in World War II. Dover Castle controlled large railway guns as well. The Admiralty Pier Guns are still in place, but not accessible to the public.