This is a classic novel by Jules Verne. In the story, Professor Hardwigg and his nephew Harry discover an ancient parchment by an alchemist named Arne Saknussemm. They travel to Iceland and climb an extinct volcano called Sneffels. With them is the Icelandic hunter Hans. They journey into the center of the earth, in which Harry gets lost. They come upon and ocean and cross it. While they are on the sea they witness a battle of ancient sea monsters. Eventually they are thrown out of a volcano on Stromboli, an island in Italy.