"We were waiting for the night."
Translation:Мы ждали ночи.
Because "ждать" is a very bad verb with its own requirements. Things that can affect their own arrival use Accusative, others use Genitive.
I am native and I think this translation is weird, because we have here no plural here Мы ждали ночь/целую ночь is more appropriate
I am not native. ночи is not plural. It is in the genitive case because, as Shady said above, with ждть things that can affect their own arrival use accusative, others use genitive. ночь cannot affect its own arrival. Hence it is in the genitive form ночи