Jungles are small to vast surface biomes that can be found on all Creativerse worlds. You might have to cross larger bodies of water to find jungles though, depending where you have started. Swamplands and Savannahs are often direct neighbours to jungles.
You can recognize Jungle-biomes by their tall Wildwood trees adorned or even covered by many Vines. Be careful when advancing, because jungles are home to aggressive red Feral Pigsies that can spawn on blocks of Detritus during the day.
Also common green Leafies and common Chizzards as well as occasional Mossy Leafies populate jungles during the day, while aggressive Night Chizzards, Night Leafies and also aggressive Night Pigsies will roam the jungles during the night. Even Night Rocksters can be encountered near small lakes or cave entries.
Jungles are usually hot biomes, so by placing torches on trees or by throwing Fire Bombs forest fires can easily be started that will then consume all blocks of Wildwood and Wildwood Leaves close enough to each other for the fire to leap over, and will only leave Beeswax, Wildwood Flowers and Vines floating in the air. As fires cannot be stopped currently (as of R32 in June 2016) other than by creating large forest aisles, you should be really careful with handling torches and all other kinds of fire in jungle biomes.
Wildwood trees come in different types and sizes; from small bushlike ones on the ground to giant Wildwood trees covered in Vines all over. You can often spot giant Wildwood trees on the area map as they are usually adorned with a bit of snow on top. Also a few parts of Wildwood trees feature Dark Wildwood Leaves and also non-glowing Wildwood Flowers - however these Flowers will just turn into common Wildwood Flowers when harvesting, and if you place them they will be the usual glowing kind.
By taking blocks of Wildwood from Wildwood trees the recipe for Bungalow Walls is unlocked (which unlocks even more bungalow-themed blocks when crafted), and by taking Vines for the first time the recipe for Thatched Walls will be unlocked. Wildwood Flowers can be used to craft Poison Resistance Potions and a number of other recipes that will accept all kinds of Flowers as ingredients.
The floor of Jungle biomes is made of Detritus that can be used for crafting as well as for building arenas to make Feral Pigsies and Leafies spawn. It seems like Horned Melons do not spawn in artificial jungles.
No Power Cells are needed to harvest Wood, Leaves, Flowers, Horned Melons and Detritus.
Wildwood Flowers can regrow on Wildwood Leaves, so in time more and more Flowers will cover the trees (or artificial biomes made from Wildwood Leaves), however really slowly.
Wood Treasure Chests can occasionally show up during (ingame-)night-times in dark places in range of view of player-characters in this biome. These valuable findings will often spawn high up in the trees tops though.
On your map, you can find jungles by searching for green areas that have dark brown lines or even crosses running through them. There are a number of small to large jungles on all Creativerse worlds. Current templates are: