The Underground City; Or, The Black Indies (Sometimes Called The Child of the Cavern)

Les Indes noires (literally The Black Indies) is a novel by the French writer Jules Verne, serialized in Le Temps in March and April 1877 and published immediately afterward by Pierre-Jules Hetzel. The first UK edition was published in October 1877 by Sampson Low, Marston, Searle and Rivington as The Child of the Cavern, or Strange Doings Underground. Other English titles for the novel include Black Diamonds and The Underground City.
From Wikipedia (CC BY-SA).