Lúcia of Fátima

“Our Lady showed us a great sea of fire which seemed to be under the earth. Plunged in this fire were demons and souls in human form, like transparent burning embers, all blackened, or burnished bronze, floating about in the conflagration, now raised into the air by the flames which issued from within themselves together with great clouds of smoke, now falling back on every side like sparks in a huge fire, without weight or equilibrium, and amid shrieks and groans of pain and despair, which horrified us and made us tremble with fear. The demons could be distinguished by their terrifying and repellent likeness to frightful and unknown animals, all black and transparent. This vision lasted but an instant. How can we ever be grateful enough to Our dear Heavenly Mother, who had already prepared us by promising us in the first Apparition, to take us to Heaven. Otherwise I think we would have died of fear and terror. We then looked up at Our Lady, who said to us so kindly and so sadly: “You have seen hell where the souls if poor sinners go. To save them, God wishes to establish in the world devotion to My Immaculate Heart. If what I say to you is done, many souls will be saved and there will be peace. The war is going to end, but if people do not cease offending God,”
― Lúcia of Fátima, Fatima in Lucia's Own Words: The Memoirs of Sister Lucia, the Last Fatima Visionary