This is a famous tiny rocky "island" few meters from Mwanza's Lake Nyanza (Victoria) shore.
It is an aatractive symbol of Mwanza, Tanzania. If you arrive in Mwanza, this is the site you should never miss. It is an attractive site indeed.
It has long history related to superstitial powers but not harmful to anybody. There are several pieces of iron bars, quite thick inserted into the rocks in a linear pattern causing no crack at all. They appear as if somebody inserted them while the rocks were in molten state and later dried up.
There is no way you can pull them out.
Historians they say that those iron bars were inserted by a witch doctor!
Local citizen usually never dare to swim near or go to those rocks