Don Bosco's vision when he went into Hell...
http://www.traditioninaction.org/religious/h092_RoadHell_1.html"Ahead of me I could see an immense cavern that extended far ahead ending in deep caves dug into the bowels of a mountain. They were all ablaze, but it was not an earthly fire with leaping tongues of flames, but a fire that made everything incandescent and white because of its high temperature. The entire cavern - walls, ceiling, floor, iron, stones, wood and coal - was white and glossy. That fire surpasses the fire of earth in heat thousands and thousands of times. Yet it did not consume what it burned or reduce it to ashes. It is impossible for me to describe that cavern in all its astounding reality.
While I looked appalled at that place of torment, I saw a lad, oblivious of everything around him, arriving with an indescribable momentum. He emitted a most shrilling scream, like one who is about to fall into a cauldron of liquid bronze. Then, jumping into the center of the fire, he too became incandescent like the entire cavern and perfectly motionless, while the echo of his dying wail lingered for an instant more. "
“Now that you have seen the torments of others, you must experience yourself what is the suffering of Hell.”
“No, no!” I cried in horror.
He insisted, but I kept refusing.
“Do not be afraid,” he told me; “it is just a taste. Touch this wall.”
I could not muster enough courage and tried to get away, but he held me back insisting:
“No matter what, it is necessary that you experience this.”
Gripping my arm firmly, he pulled me to the wall, saying:
“Touch it at least once, so that you may prove that you have visited the walls of eternal torments and you may comprehend how terrible the last wall must be if the first outer one is so unendurable. Can you see this wall?”
I looked at it carefully. It seemed incredibly thick. My guide continued:
“There are one thousand walls between this and the real fire of Hell. One thousand walls surround it. Each wall is very thick and is one thousand miles from the next one. This wall, therefore, is one million miles from Hell's real fire. It is just a remote beginning of Hell itself.”
When he said this, I instinctively pulled back, but he seized my hand, forced it open, and pressed it against a stone on that first of the thousand walls. The burning was so intense and excruciating that I leaped back with a scream and I woke up.
I found myself sitting on my bed, my hand was stinging and I kept rubbing it to ease the pain. As daylight came, I noticed that it was actually swollen. That dream and the impression of that fire had affected me so much that the skin of my palm had peeled off.
Bear in mind that I have not told you things in their most horrible cruelty in order not to cause you too much terror. We know that Our Lord always portrayed Hell in symbols because, had He described it as it really is, we could not understand. No mortal can comprehend these things. Our Lord knows them and He reveals them to those He chooses.