When christians speak of hell, what do they mean with it? Most christians do not know exactly where they are talking about. Hell was a wrong translation of the Gehenna, which is the Hinnom valley where the Jews used to offer their children to Molcoh. Yes they did. In the days of Jesus it was a garbage dump where the garbage was burned. In the future after His second coming this location will be a kind of a crematory for the dead bodies of trespassers that were punished to death for their sins.
Then there is the Tartaros, which is a prison under the earth where the fallen angels are being kept imprisoned. I am not even sure if there is fire down there, but yhere could be tuns of water in it, as we read in Genesis 7:11. Whatever this Tartaros is, there are no humans in it. Only Jesus descended into it after His resurrection. One needs at least to have a resurrected body to descend into the Tartaros.
Then there is the Lake of Fire which is probably the Dead Sea. In the next aion this Dead Sea will be fresh fishing water. But no one knows what will happen with it later. The devil, the Beast and the false prophet will be cast into this lake of fire. Also humans will be cast into it. But they will be already punished to death when they are thrown into this lake. They are the one whose names are not written in the Book of Life. They will encounter a second death. For them there will also be a second resurrection because 1 Corinthians 15:28 teaches that after the fifth aion when death will be abolished, God will be All in All. Whatever this lake of fire is; it is not a lake where people will be punished forever for their sins. First of all, the one who are being cast into this lake are already dead. Secondly, there is no such a thing as eternal punishment in the Bible. The word eternal was a wrongly translation of the word “aion” which is a temporal period of time.
Another hell fire is the fire of Babylon. In Jeremiah 21:10 we read how Babylon destroyed Jerusalem by fire. As a rebuild Babylon herself (Zacharia 5:11) will be destroyed by fire in the Endtimes, as we read in Jeremiah 51:58. Medieval christians considered these fires as the hell fires.