Urfa is supposedly the birthplace of Abraham (called Ibrahim in Arabic, he was an important prophet) and henceforth an important Islamic place of pilgrimage. Around the site of the cave are a number of mosques built around a park with water features. One of these mosques, the Halil-ur-Rahman has a pool (called the Balikligöl) occupied by a rather large number of holy fish. It is said that anyone who catches one of these will go blind. That said the story behind the pool is quite interesting: The pool is at a site where Nemrut (there's a legend claiming him to be the builder of the tower of Babel) wanted to burn Abraham as a sacrifice. God however intervened and turned the pyre into water and the coals into fish, thus saving Abraham. Legend also names it as the birthplace of Job.