Maybe, the world's largest coastal guns are located outside of Harstad, 120 km north of Narvik. On the hillside to the North of Harstad, on Trondenes (still a Norwegian Military base), the Germans placed 4 giant canons which had a calibre of 40,6 cm!
The Germans placed 7 (4 in Trondenes and 3 further south on Engeløy) guns like this to cover the Vestfjord/Ofotfjord into Narvik, and both the batteries called 'Batteri Theo' in Trondenes, and 'Batteri Dietl' on Engeløy had the range to cover the fjords 50-60kms away.
The guns could fire 3 different kinds of ammuntion: The yellow HE-shell, the blue semi-piercing shell and the black so called 'Adolf'-shell. The 'Adolf'-shell was lighter to be able to be fired across longer distances, but retained the same explosive power as the regular HE-shell.
The shells used two different types of charge to set the round off. First you inserted the shell into the barrel, then the clothed middle-charge, and at last the cased charge. At the left you see the clothed middle charge, and to the rigt the cased charge.
Around the gun itself, a huge bunker area and the ammo-pit was located. Down here 49 German soldiers worked both to feed the gun with ammo and to feed it with info needed to fire the gun accuratly. Small trolleys were used to transport the shells around the gunpit to the lift area.
The 406mm SK C/34 giant guns had been designed in 1934 by Krupp to arm the projected H-39 class battleships. As the vessels were cancelled, the seven guns built were sent to coastal batteries in Harstad and Blanc Nez near the English Channel.
After the end of the war the Trondenes guns were taken over by the Norwegian Army, along with 1,227 shells. The battery was last fired in 1957 and formally decommissioned in 1964. The three Engeløya guns were sold for scrap in 1956 but the four guns at Trondenes were spared and one is open as a museum. In the summer there are normally three or four guided tours per day