These areas of forest and dense jungle produce relatively poor amounts of food and no resources. But they can be made much more valuable by conversion into either Grasslands or Forest. For this reason, the long term potential of a city site containing several Jungles is good.
Jungles produce 1 food. Gems can be found in Jungles which generate an extra 4 trade.
It costs 2 Movement Points to travel over a Jungle region.
Jungles offer a +50% defense bonus.