There are three groups in Bosnia; the Catholic Croats, Orthodox Serbs and Muslim Bosniacs. In 1991, Bosnia-Herzegovina's president, Alija Izetbegovic decided to seek independence. The Croats and Bosniaks were behind this move for independence. The Serbs did not want it so in 1992, the Serbs made their move and began a course of ethnic cleansing. A horrific war continued and eventually the Croats and Bosniaks turned against one another.
In November 1993 the Croats bombed the bridge and it fell into the river. This was a strategic move in order to cut off the Bosniaks on the east and west banks.
The bridge was rebuilt after the war hoping for reconciliation. That is still a work in progress and unfortunately will most likely take generations.