A modern classic, free for a limited time :)
Rushing home one day, Professor Otto Lidenbrock puts himself to work trying to decipher the meaning of an ancient Icelandic text. After some time on an Otto-imposed hunger strike, Otto's nephew Axel finds the translation. This ancient document claims that it is possible to reach the center of the earth! Immediately Otto and Axel leave for Iceland, find a guide named Hans, and set out for the volcanic crater that is to be the entrance to the depths of the planet.
Despite bad weather obstructing their progress, the trio finally manages to enter the crater. After rapelling down, the group starts to encounter all of the terrors and wonders that Verne himself expects a group to find based off (for Verne) recent scientific discoveries. There are rooms full of natural gas, underwater rivers, and vast caves that allow for people to communicate despite being separated by great distances. As the book reaches its climax, the three men find dinosaurs doing battle, as well as evidence of subterranean prehistoric human-like creatures. However, they find that the passage that was supposed to take them to the center of the earth is, in reality, a giant pit that would result in their deaths. Upon finding this pit, they trigger a raging flood, by which the three men are carried thousands of miles to Italy, where they finally exit the subterranean world by way of another volcanic crater.
As always, enjoy :)