From the World Heritage inscription:
The Old Bridge area of the Old City of Mostar, with its exceptional multicultural (pre-Ottoman, eastern Ottoman, Mediterranean and western European) architectural features, and satisfactory interrelationship with the landscape, is an outstanding example of a multicultural urban settlement. The qualities of the site’s construction, after the extremely ravaging war damage and the subsequent works of renewal, have been confirmed by detailed scientific investigations. These have provided proof of exceptionally high technical refinement in the skill and quality of the ancient constructions, particularly of the Old Bridge. Of special significance is the Radoboija stream, which enters the Neretva on its right bank. This provided a source of water for the growing settlement, and from it springs a number of small canals used for irrigation and for driving the wheels of water-mills.
There has been human settlement on the Neretva between the Hum Hill and the Velez Mountain since prehistory, as witnessed by discoveries of fortified enceintes and cemeteries. Evidence of Roman occupation comes from beneath the present town.
Little is known of Mostar in the medieval period, although the Christian basilicas of late antiquity continued in use. The name of Mostar is first mentioned in a document of 1474, taking its name from the bridge-keepers (mostari ); this refers to the existence of a wooden bridge from the market town on the left bank of the river which was used by soldiers, traders, and other travellers. At this time it was the seat of a kadiluk (district with a regional judge). Because it was on the trade route between the Adriatic and the mineral-rich regions of central Bosnia, the settlement spread to the right bank of the river. It became the leading town in the Sanjak of Herzegovina and, with the arrival of the Ottoman Turks from the east, the centre of Turkish rule.
The town was fortified between 1520 and 1566, and the bridge was rebuilt in stone. The second half of the 16th century and the early decades of the 17th century were the most important period in the development of Mostar. Religious and public buildings were constructed, concentrated on the left bank of the river, in a religious complex. At the same time many private and commercial buildings, organized in distinct quarters, known as mahalas (residential) and the bazaar, were erected.
The old bridge in Mostar is actually not that old. At least the current incarnation of it is not. Originally built in 1557 under the administration of the Ottoman Empire, it was destroyed by Bosnian Croat forces in November 1993 during shelling of the town. The Bosnian Croat forces later admitted that they purposely targeted the bridge for destruction because they felt it was of strategic importance. (After the way, experts testified that the bridge wasn’t strategically important. The bridge was attacked because of its cultural significance.)
In 1998 UNESCO helped in the recreation of bridge which was completed in 2004, with the bridge being listed as a World Heritage Site in 2005.
The scars from the Bosnian War can still be seen in Mostar. Bullet holes can be seen in many buildings and a few still remain gutted. Although there is peace, the city is still divided between Croats and Muslims, a situation which is unlikely to change anytime soon.
I visited Mostar on a day trip from Dubrovnik, which is probably the easiest way to visit the city. There are tours leaving Dubrovnik daily.