From what I have heard, Knowles always had idyllic plans for this particular exhibit - in his own autobiography, 'My Marwellous Life' [2009] he speaks of how, when finances were permitting, this large field would become an exhibit of African grazing-animals [which it definitely is now, though perhaps Knowles wanted more of them? We may never know...] but as well as this, he also wanted, adjacent to it a large enclosure of lions, and if viewed from one point, the lions to almost look immersed in the same savannah of the grazing herbivores.. though the herbivores knew they were in no immediate danger!
There have been developments to the field and valley of course, but not quite like this!