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.
Twists and turns
You should read this book. It has many twists and turns in it once it gets started. It took me a fair amount of time to get into the story but once i did,it was an interesting read.
Long lost classic!
This should be one of the more common Jules Verne tales. It is classic in the sense of its respect for goodness and abhorrence of evil. The protagonists are exemplary in character and the ensuing love story is a gem of classic purity and heroism. Too bad this is a story that has been largely forgotten in the vaults of time.
Another vivid scenario for a great relate from prolific & prodigious Verne! Fantasy and legends mingle with thrill and suspense to produce a great story that keeps you hooked to the very last page!