Snowleopard, this exhibit is only ten years old and should not be judged from this angle alone, I have visited Hannover Zoo and can confirm that the exhibit is much larger than seen here. Indeed, if I remember right, there are two, this is the smaller one. So please don't be so harsh all the time. A photo may say more than 1000 words but still not the whole truth.
There is only one bull exhibit, and this one is defintely two small for an elephant bull, its not much larger than it can be seen on the picture. The whole keeping of elephants at this zoo is completly outdated, altough the exhibit is only 10 years old.
Whats worse, it's very boring, no bath, no mudhole, to less shade, no contact to the other elephants....