I decided to give it a go, just to relax a bit.
It turned out to be a great wonder. It reminds me of one of my favourite parks: Munich's English Garden. Both have a long-ranging woody and park areas, structured in a mostly organic, i.e. purposely unstructured, way. I saw a lot of trees, and this autumn, my favourite time of year, so there was an explosion of many-hued leaves - everywhere, of course also away from the trees, on the wire mesh of animal cages, on the paths, in the water. Magic.
It's the 1st zoo's poorer brother, but a heck of a lot larger. You keep getting surprised: I was sitting at one of the cafés, having a Bockwurst with mustard, and some bubbly (mineral water ) , when I realised that a nice big lawn not far away, stretching about a mile away to a seam of dark trees, with a flight of orange flamingos in its centre, was more than it seemed - a tranquil dromedary slowly ambled into view. I later got up and walked over and saw that I'd been observing the dromedary enclosure - one with a moat instead of a fence, and a whole herd of the desert ships in this incongruent northern oasis!
As always the polar bears - and Cape Buffalo! - were impressive, but the lasting impression is of a beautiful and laid-back park, that one can get lost in easily for a day! (More! )
At the end of my visit, I rested for a bit in a beautiful structured garden next to the "castle"* Friedrichsfelde, which is part of the zoo. Here noble folks some centuries back probably took afternoon walks, thinking about nature and (human) beauty, in synchronicity (witness many statues of children playing with various beasts).
A place to recommend! I will visit it again, I'm sure, to catch up for more than a decade - my time in Berlin - of ignorance.
(* actually just a grand old palace of a house, with pink and white exterior)