Before I start... Two things. 1: The reason I'm kind of talking a lot about it lately is because its rarely talked about but very important to know in terms of the Catholic, and other christian, faiths. 2: This is what I believe in combination of what I've read from the Catholic bible, what I've heard from several educated Catholics, and what I myself believe.
So, to start off... Hell is basically a state of being in which you are in complete and total separation of God. It is less of a place and more of a state of being for the soul, as far as I know. Though hell may or may not be actually a place as well with fire and brimstone, and all that dramatic stuff.
A lot of people believe hell is simply an invention of the church as a blank threat to control the minds of the public. Well, its not. Jesus talks about hell quite a lot. In fact, if you read the four Gospels VERY, VERY carefully, more is said about hell by Jesus himself than in the rest of the books put together. And also, a lot of people say hell was never mentioned in the old books, the Jewish books. Well... That is actually true. BUT, there is mention of a place, Sheol, an abode where the dead reside without God. I'm not entirely sure what that is, but... According to one of my Jewish friends, that's not what they currently believe in. As well, the concept is NOT unique to the Jewish faith. The concept of a place of eternal suffering is also in the Greek religion, Hades. ... That's all I've got for now, but there are probably several others with similar things.
Now, about entering hell... There's a misconception that God sends you to hell. Now, that's not exactly true... The person sends themselves to hell. Before Jesus died for our sins, all sinners went to hell. When Jesus died for our sins, he paid a debt he did not owe so all who were imperfect sinners still had a chance to get in to heaven. Even if you should be punished for the worst of sins, it is not God's justice that sends you to hell. God's love and mercy overpowers that. Now, if you are both a sinner and absolutely REFUSE to accept God's invite to heaven through his ultimate love and forgiveness, then he will not stop you from going to hell, since that is what the soul wants: to be separated from God and not with him from eternity. God NEVER stops loving you. Hell is the place you go when YOU stop loving HIM and refuse to accept His invitation to be in eternal communion with him.
Now, to me, that does not mean non-Catholics get auto-sent to hell for not believing in God, Jesus, and the Holy Spirit. Jesus died for EVERYONE, not just Jews. And, yes. Jews. Jesus was a Jewish person who wanted to make Jews better Jews. God still loves everyone, whether they know Him or not. Everyone gets an invite to heaven. And, at the end of your life, if you were an okay guy who just happened to not be baptized and confirmed Catholic, you'll just have to wait in purgatory, the divine waiting room, for a little bit before coming to eternal paradise.
As well, hell is not a place where everyone is stuck for eternity with no chance of escape. Hell is a state of being, like I said. When you are in hell, you keep God locked out. The doors of hell are locked, but from the inside. He wants to be in relationship with EVERYONE, even if you're the worst person in the world. Like... King Leopold II. (Could've said a certain German, but that guy is too overused as a representation of evil ^^; ) At any time, a sinner in hell is allowed to use God's invitation to enter the kingdom. The second a sinner in hell repents, he's instantly in heaven.
With all that said, here's the final thing. The demons, fallen angels, and the devil. Lucifer, the devil, Satan, is constantly thought of as like the ruler of hell, a divine sadist of sorts, who punishes people that God casts down to hell. Now, that's not necessarily true. If anything, he is the MOST tortured in hell. God made Lucifer a Seraphim. That's like the highest in command of all the choirs of angels. The word seraphim comes from the Hebrew word Burning One, as the seraphim are like the highest of the high, burning with the glory of God. God gave Lucifer all the knowledge of the universe, the highest power, besides His, and yet Lucifer tried to prove he was better than God. Lucifer refused to be with God, so he fell. Hard. In fact, he fell from so high, the suffering he feels is worse than what another in hell feels. And what's worse, he never ceased to burn with God's glory. God's love is PAINFULLY present to him, despite their separation. However, he's not just suffering only. He still causes a LOT of evil with the help of his fellow demons, the fallen angels who fell with him. But, he's in pain along with those in hell.
Now, for my hope. As hell is, in theory, escapeable, I truly believe that in the end, it will be empty. Not just of human souls, but of the angels who defied God. One by one, I pray they will all want to join God in eternal paradise. Eventually, hell will be empty of human souls, then of fallen angels. Finally, the ultimate evil, Lucifer, will realize the error of his ways, and finally return to God. Now, that's just a hope. Of course, I don't think emptying hell will be easy, and it may take half an eternity. But... It will be.
Well, that's what I believe about hell. Not trying to convert anyone. Just telling people what I myself have found to be true, and what I believe might happen. Have a good day now :3
P.S.: Any comments saying "That's wrong! You're stupid, and here's the RIGHT answer:", will be noted. I just won't reply to them.