Today's classic is Journey to the Centre of the Earth (1864) by Jules Verne.
The intrepid Professor Lindenbrock embarks upon the strangest expedition of the nineteenth century: a journey down an extinct Icelandic volcano to the Earth's very core. In his quest to penetrate the planet's primordial secrets, the geologist - together with his quaking nephew Axel and their devoted guide, Hans - discovers an astonishing subterranean menagerie of prehistoric proportions. Verne's imaginative tale is at once the ultimate science fiction adventure and a reflection on the perfectibility of human understanding and the psychology of the questor.
You can read this classic online for free at The Literature Network.
Did you know there was a movie adaptation (sort of a current day sequel or follow-up) released in 2008 starring Brendan Fraser?
Have you read Journey to the Centre of the Earth or anything else by Jules Verne?