A look around London Zoo (North end of Regent's Park).
So much to see, I should have allowed a day rather than just my afternoon visit.
All sorts of things to see there from small to large. (However don't expect too many of the larger creatures, most of them are now up at Whipsnade.)
It's nice that a selection of paths and walkways actually take you into and through some of the animal enclosures, so there's only a rope or wooden rail between you and them.