Quote Originally Posted by heartfelty View Post
A number of ancient cultures developed in the huge territory, USSR.

'Number' is feminine noun.
'ancient' is feminine adjective.
'cultures' is feminine plural.
'developed' is past imperfective.
'huge' is feminine adjective
'territory' is feminine noun, prepositional?

Несколькая в античный культуры развивала на громадная территориу, USSR.
"A number" in Russian is not a noun it is translated as несколько and it could be an adverb or a numeral (as in here)
"ancient" is an adjective and the gender of an adjective depends on following noun, because culture is feminine, ancient will be feminine too
"territory" is a feminine noun but it looks more like translative case which doesn't exist in Russian I have no idea what case is here but most likely accusative

I think chaika got almost correct translation for your sentence
This is how I would translate it
Несколько древних культур развились в огромную территорию - СССР