could any of the kingdoms at middle earth attack the southern continents?

[Zigûr]

Originally Posted by tom the eldest

At the height of its might,gondor could invade the southern continents,but the casualties will be massive,and the invasion could be called of after weeks of months.afterall,they fight in a completely unfamiliar terrain,a massive jungle.

How do you know they could invade? Or if they did, that the casualties would be massive? Or that the invasion would be called off? Or that the terrain was unfamiliar? None of these things are written about. For all we know Gondor had an elite jungle fighting unit.

Originally Posted by tom the eldest

Well,looking at the map,its looks like the south continent did have large forest and jungles.and in the two towers,one of the quote says "like monkeys in the jungles of the south".

According to which map? And do you mean Harad or the actual, separate Southern Continent? Because in the Ambarkanta map, the "Dark Lands" aren't given any detail - forests, mountains or anything else. Their presence in the maps from, say, Karen Wynn Fonstad's Atlas of Middle-earth is pure speculation. I always assumed also that the reference to "apes in the dark forests of the south" was a reference to Harad, not the "Dark Lands."

Originally Posted by tom the eldest

the dark lands are separate from middle earth and far harad

Far Harad, like the rest of Harad, is part of Middle-earth. Sorry to be pedantic about this but I think it needs to be emphasised to minimise confusion.