The following passages are taken from the Diary of St. Faustina and they refer to her visions of Hell, Purgatory and Heaven.
"...I Saw two roads. One was broad, covered with sand and flowers, full of joy, music and all sorts of pleasures. People walked along it, dancing and enjoying themselves. They reached the end without realizing it. And at the end of the road there was a horrible precipice; that is, the abyss of hell. The souls fell blindly into it; as they walked, so they fell. And their number was so great that it was impossible to count them. And I saw the other road, or rather, a path, for it was narrow and strewn with thorns and rocks; and the people who walked along it had tears in their eyes, and all kinds of suffering befell them. Some fell down upon the rocks, but stood up immediately and went on. At the end of the road there was a magnificent garden filled with all sorts of happiness and all these souls entered there. At the very first instant they forgot all their sufferings" (Diary 153).
Hell: " Today, I was led by an Angel to the chasms of hell. It is a place of great torture; how awesomely large and extensive it is! The kinds of tortures I saw: the first torture that constitutes hell is the loss of God; the second is perpetual remorse of conscience; the third is that one’s condition will never change; the fourth is the fire that will penetrate the soul without destroying it, a terrible suffering, since it is a purely spiritual fire, lit by God’s anger; the fifth torture is conditional darkness and a terrible suffocating smell, and despite the darkness, the devils and the souls of the damned see each other and all the evil, both of others and their own; the sixth torture is the constant company of satan, the seventh torture is horrible despair, hatred of God, vile words, curses and blasphemies. These are the tortures suffered by all the damned together, but that is not the end of the sufferings. There are special tortures destined for particular souls. These are the torments of the senses. Each soul undergoes terrible and indescribable sufferings, related to the manner in which it has sinned. There are caverns and pits of torture where one form of agony differs from another. I would have died at the very sight of these tortures if the omnipotence of God had not supported me. Let the sinner know that he will be tortured throughout all eternity, in those senses which he made use of to sin. I am writing this at the command of God, so that no soul may find an excuse by saying there is no hell, or that nobody has ever been there, and so no one can say what it is like. I, sister Faustina, by the order of God, have visited the abysses of hell so that I might tell souls about it and testify to its existence. I cannot speak about it now; but I have received a command from God to leave it in writing. The devils were full of hatred for me, but they had to obey me at the command of God. What I have written is but a pale shadow of the things I saw. But I noticed one thing: that most of the souls there are those who disbelieved that there is a hell. When I came to, I could hardly recover from the fright. How terribly souls suffer there! Consequently, I pray even more fervently for the conversion of sinners. I incessantly plead God’s mercy upon them. O my Jesus, I would rather be in agony until the end of the world, amidst the greatest sufferings, then offend You by the least sin. (Diary 741).
Pugatory: " ...I saw my Guardian Angel, who ordered me to follow him. In a moment I was in a misty place full of fire in which there was a great crowd of suffering souls. They were praying fervently, but to no avail, for themselves; only we can come to their aid. The flames, which were burning them, did not touch me at all. My Guardian Angel did not leave me for an instant. I asked these souls what their greatest suffering was. They answered me in one voice that their greatest torment was longing for God. I saw Our Lady visiting the souls in Purgatory. The souls call Her “The Star of the Sea”. She brings them refreshment. I wanted to talk with them some more, but my Guardian Angel beckoned me to leave. We went out of that prison of suffering. [I heard an interior voice which said] ‘My mercy does not want this, but justice demands it. Since that time, I am in closer communion with the suffering souls.’” (Diary, 20)
Heaven: " November 27, 1936. Today I was in heaven, in spirit, and I saw its unconceivable beauties and the happiness that awaits us after death. I saw how all creatures give ceaseless praise and glory to God. I saw how great is happiness in God, which spreads to all creatures, making them happy; and then all the glory and praise which springs from this happiness returns to its source; and they enter into the depths of God, contemplating the inner life of God, the Father, the Son, and the Holy Spirit, whom they will never comprehend or fathom. This source of happiness is unchanging in its essence, but it is always new, gushing forth happiness for all creatures. Now I understand Saint Paul, who said, “Eye has not seen, nor has ear heard, not has it entered into the heart of man what God has prepared for those who love him.” And God has given me to understand that there is but one thing that is of infinite value in His eyes, and that is love of God; love, love and once again, love; and nothing can compare with a single act of pure love of God. Oh, with what inconceivable favors God gifts a soul that loves Him sincerely! Oh, how happy is the soul who already here on earth enjoys His special favors! And of such are the little and humble souls. The sight of this great majesty of God, which I came to understand more profoundly and which is worshipped by the heavenly spirits according to their degree of grace and the hierarchies into which they are divided, did not cause my soul to be stricken with terror or fear; no, no, not at all! My soul was filled with peace and love, and the more I come to know the greatness of God, the more joyful I become that He is as He is. And I rejoice immensely in His greatness and am delighted that I am so little because, since I am little, He carries me in His arms and holds me close to His Heart. O my God, how I pity those people who do not believe in eternal life; how I pray for them that a ray of mercy would envelop them too, and that God would clasp them to His fatherly bosom... " (Diary 777).