At the Straits of Calais were several gun emplacements that could bombard England. One of the most famous is Batterie Todt. This complex consisted of four huge bunkers (Turm’s) with 380mm Siegfried cannons. Originally intended as a naval artillery guns but were later used as railway artillery.
The barrel of a gun weighed 103 tonnes and had a length of 19 meters. It could shoot a projectile of 490 kg 55 km far. A projectile of 790 kg 53 km. The light projectile(490 kg) took about 33 seconds to reach Dover, the heavier took 9 seconds longer(the difference was over 600 meters in depth and 64 meters laterally).
Today Turm 1 is a museum and the other Turm’s are found nearby. None of them have any cannons anymore.