<P> In the city port area, one of the most significant areas of the maritime trade city, there were two entrances: the Gate of Ponte (port) and the Fishmarket Gate . The entire layout of the Dubrovnik streets, as well as a range of expansions, was intended for fast and effective communication with the forts of the city walls . </P> <P> Constructed in 1476, the Gate of Ponte is situated westwards from the Great Arsenal . The city wall, built at the same period, leads from the Gate to St. John Fortress . The present - day street of Damjan Juda was formed in the 15th century when the sewage system was completed, and building houses against the western city wall was no longer allowed . </P> <P> The Fishmarket Gate, built in 1381, stands eastward from the Great Arsenal . The three arches of the 15th century Small Arsenal, where small boats were repaired, are situated a bit further . The old tower of St. Luke's protects the harbour in the east, and the harbour entrance is encircled and guarded by the Revelin Fortress . </P> <P> The fall of Constantinople in 1453 to the Ottomans was a clear sign to the cautious citizens of Dubrovnik that ample defensive measures were quickly needed, the strengthening of its defensive structures the foremost of the issues . The fall of Bosnia, which followed soon in 1463, only hastened the works . As a result, the Republic invited the architect Michelozzo di Bartolomeo of Florence to direct the improvement of the city's defenses . His work in Dubrovnik resulted in the construction and expansion of numerous buildings of key importance for the defense of Dubrovnik . </P>

Which cities in croatia are famous for their protective walls and forts