The fort of Kljuch is located on the left bank of the Sana river, overlooking the present town of Kljuch. It rises in a position with outstanding natural defences, at the intersection of two ancient roads. Kljuch is one of the oldest forts in Bosnia and Herzegovina, built most probably during the 13th century. It was used till the end of 19 century. It is interesting to see how this fort, built before the time of the firearms, was adapted to the defence of firearms later in time.