Andersen's fairy tales

In Denmark there stands an old castle named Kronenburg, close by the Sound of Elsinore, where large ships, both English, Russian, and Prussian, pass by hundreds every day. And they salute the old castle with cannons, Boom, boom, which is as if they said, Good-day. And the cannons of the old castle answer Boom, which means Many thanks. In winter no ships sail by, for the whole Sound is covered with ice as far as the Swedish coast, and has quite the appearance of a high-road. ...