The Iceberg Express by David Cory

For a few minutes Mary Louise felt quite lonely. Presently she asked the Polar Bear to be kind enough to land her on the nearest shore.

At once the big kind animal trimmed in his sail and before long they entered a beautiful bay whose dark waters were dotted with the white sails of the fisher boats, and directly in front, climbing up to the sky, a high mountain on which stood a castle, where from a tall tower all night long shone a light that could hardly be told from the stars around it.