Chagiga 13B - River of Fire

1. How is the river of fire created?
2. The function of the river of fire after people die
3. The connection between דונור  and ירדן
4. A suggestion as to how to connect the creation of the river and its connection to Yarden
5. The 974 lost generations...what exactly happened to them? Why?
6. Sources the explain where those generations manifested themselves in history