As far as lighting inspiration goes, you have to see this:
Over 35 years ago in the middle of the Darvaz region of Uzbekistan (as the story goes), a mining company was digging for gas and stumbled upon a monstrous underground cavern. This cavern was so full of gas that no one dared to enter the cavern – so the geologists in the mining company decided to ignite the gas in order to get rid of it. Instead what happened was they started an ever-burning hole of fire that has apparently been burning for over three decades. This thing is crazy.
Check out these images, taken by John H. Bradley:
Thanks, English Russia!