Passage: Journey to the Center of the Earth (French: Voyage au centre de la Terre, also translated under the titles A Journey to the Centre of the Earth and A Journey to the Interior of the Earth) is an 1864 science fiction novel by Jules Verne. The story involves German professor Otto Lidenbrock who believes there are volcanic tubes going toward the centre of the Earth. He, his nephew Axel, and their guide Hans descend into the Icelandic volcano Snæfellsjökull, encountering many adventures, including prehistoric animals and natural hazards, before eventually coming to the surface again in southern Italy, at the Stromboli volcano.

Question: Lidenbrock is the main character in what novel?
A Journey to the Interior of the Earth