Summary:

This is a fictional hollow earth adventure. The narrator, Olaf Jansen, is a Norwegian who sails with his father deep into the northern ice. There they sail over the lip of the hollow earth, and into the inner world, lit by a dim central sun. The inhabitants are an advanced race of giants who have electricity, monorails, and extremely long lifespans. The travelers return to the surface through the Antarctic, but lose everything which could confirm their tale on the return voyage.