Hole-y cheese! More than 24 million Geronimo Stilton books in print!I, Geronimo Stilton, was off to the wildest part of Brazil — the Amazon jungle! My friends and I were hunting for an extremely rare crystal treasure, which was guarded by a native tribe and located in the heart of the forest. We'd have to navigate through crocodiles, giant rats, piranhas, and other dangers to get there. Holey cheese! What an adventure!