Yup. They were called nukes.
Back in 1993 I was traveling in Central Europe with a guy who had been in a chemical warfare unit of the US Army. We were on some bluffs overlooking Budapest and he said that in his head he was still looking at the contours of the land and the river basin thinking about where the best place would be to target the nerve gas shells for maximum effect.
Sounds nasty and it was, but being prepared to do the unthinkable yourselves is what prevents your opponents (if they're sane, hence the problem with North Korea) from doing it to you. It's call deterence and democrats used to understand the concept.