The big outdoor exhibit for Indian rhinos in Berlin Zoo. They have two, I think, and they also have access to their indoor exhibits, which aren't this big.
@Zebraduiker: All valid points. I wonder whether the Indian Rhino exhibit in Vienna fulfills at least partly the aspects mentioned here. I'll take a look at it the next time I'm there.
@Sun Wukong. I don't know, but I belive, they have soft floor inside and outside, you knwo, because the problems with their feet, which have most of all indian rhinos in europe, because they are being kept on to hard ground. I hope to see someday in the future, after all zoos are full of elephant bulls and elephant babies are to boring for the visitors, a big indian rhino indoor exhibit, built after my ideas.
I know really only one excellent and unuasally holding of that species, at the San Diego WAP.