The original zoological and botanic
gardens were partially destroyed during the Great Global Event. In fact it
turned out to be something of a blessing in disguise as the resulting
mountain of warm, fertile material allowed the zoo to expand considerably
and the newly forming jungle began to provide a unique and productive
habitat - a tropical forest in England (well a tiny corner is actually in
Wales, but they've disowned it as culturally un-Welsh.) However time and
unnaturally rapid evolution, combined with unknown substances unique to
this bit of hillside, transformed the jungle into a most intimidating place.
Mutants are rumoured to wander there and stories abound of sinister
goings-on and disappearances. It is surrounded by two tall lines of very
strong high-security fencing; this not only contains the jungle and keeps the public
out, but also magnifies its perceived mysteries. A strange and immensely
powerful force is said to exist there.
The apparent strategic importance of Nesstown Zoo and the incomparable nature of some of its animals and plants, combined with widespread hearsay and undoubted fear of the unique Dung Jungle, have made it a target for numerous attempts to wrest it's darkest secrets for use both in warfare and to dominate the world commercially. However, the two most powerful organisations, magalomaniac Monantos Corporation, and the US military have, so far, failed to get their ways.
Moreover, it is common knowledge that multi-cultural inter-species interactions at Nesstown Zoo can cause tensions not found anywhere else in the animal kingdom beyond humans. A fine example being the Proletarian Penguin Peoples Party (4P) and its dislike of anything hairy or furry, or intellectual. The 4P are known for both capriciousness and belligerence. It is also the case that there are some higly intellectual residents in the zoo. Despite attempts at mediation these clashes continue to this day and often impinge on local human society.
Now the UK government have made Nesstown Jungle a SSSI, forbidden to unauthorised visitors, and the United Nations have made the whole zoo's unique and diverse community a World Heritage Site. In doing so effectively they stopped anyone doing anything to improve the situation.