In the Middle Ages, virtually all large cities had city walls – Dubrovnik in Dalmatia is a well-preserved example – and more important cities had citadels, forts or castles. Great effort was expended to ensure a good water supply inside the city in case of siege. In some cases, long tunnels were constructed to carry water into the city. In other cases, such as the Ottoman siege of Shkodra, Venetian engineers had designed and installed cisterns that were fed by rain water channeled by a system of conduits in the walls and buildings.Karaiskaj, Gjerak. "Furnizimi me ujë i kalasë së Shkodrës ne mesjetë." Monumentet: Materialet e sesionit III shkencor të Institutit të Monumenteve të Kulturës 11 (1985): 55–77. Complex systems of tunnels were used for storage and communications in medieval cities like Tábor in Bohemia. Against these would be matched the mining skills of teams of trained sappers, who were sometimes employed by besieging armies.
In the Middle Ages, virtually all large cities had city walls – Dubrovnik in Dalmatia is a well-preserved example – and more important cities had citadels forts or castles. Great effort was expended to ensure a good water supply inside the city in case of siege. In some cases, long tunnels were constructed to carry water into the city. In other cases, such as the Ottoman siege of Shkodra, Venetian engineers had designed and installed cisterns that were fed by rain water channeled by a system of conduits in the walls and buildings.Karaiskaj, Gjerak. "Furnizimi me ujë i kalasë së Shkodrës ne mesjetë." Monumentet: Materialet e sesionit III shkencor të Institutit të Monumenteve të Kulturës 11 (1985): 55–77. Complex systems of tunnels were used for storage and communications in medieval cities like Tábor in Bohemia. Against these would be matched the mining skills of teams of trained sappers, who were sometimes employed by besieging armies.