Gehenna Valley. Once apparently a city dump for Jerusalem and possibly a place where Israelites sacrifice to idos. Jesus used it as a symbol of God's punishment for sin, perhaps because some thought that the idol sacrifices offered there were a reason God let the Jews get conquered and exiled. When Jesus talks about the valley in those terms, translators created an English word to express the idea: Hell.
Map Gehenna Valley
Map Gehenna Valley, location of an ancient trash heap and where Israelite kings once sacrificed their sons.
Gehenna trash heap