Hi, I'm currently writing a Sci-Fi novel, set on another planet. Part of the story involves the main characters entering a city, and realizing it had been made uninhabitable due to an attack that happened around 250 years prior, so they cannot enter safely. This will also be the same with a few other cities they encounter.
I want the story to be as scientifically accurate as possibly. I tried the "nuclear attack" route, but soon found that most nuclear effects wouldn't be all that dangerous after 250 years. I then thought about going down some kind of poisonous gas route, but common sense told me it would have diffused long ago.
I really want to give a feeling of dread, as the characters realise they are entering a dangerous area, and have them looking to get out as quick as possible.
So my question is, as the title says, what would make an area uninhabitable for over 250 years? Is there anything, or will I have to shorten the time to 50/100 years ago?
Also, I could have it that the cities are safe to travel through, though I don't feel as though it would be relevant to the story, and might end up having to write for a city that has no significance to the story, other than the fact it was attacked. Though if people advise me this way may be better, then this is how i will do it.
This is my first novel, so if you can't answer the question, but have any kind of advice to give, please feel free to give your input.
P.S I'm writing this novel for myself, I don't intend to publish it. Though, if i like how it turns out, i may want to publish it as a Kindle ebook. Though as of right now, it's just a hobby lol
Added (1). Thanks for the fast responses guys!
I should have mentioned this was a kind of guerrilla attack, from a nearby alien planet
Anyway, I like the idea of fumeroles/underground coal veins, never really thought of going for a 'chain reaction' lol. I could have it that the attackers strategically targeted certain areas with explosives, to release these gases on to the city, if that would work out right?
Anyway, thanks for the help, greatly appreciate it, as this is the biggest bump in the road I've had since i started writing lol
См. статью: What would make an area uninhabitable for over 250 years?