During the Swedish rule, the Old Town of Narva was built. Following a big fire in 1659 that almost completely destroyed the town, only stone buildings were allowed to be built in the central part of the town. Incomes from flourishing trade allowed rebuilding of the town center in two decades. Until World War II, the baroque Old Town underwent practically no changes, and thus became renowned all over Europe. Towards the end of Swedish rule, the defense structures of Narva were greatly improved. Beginning in 1680s, an outstanding system of bastions, planned by the renowned Swedish military engineer Erik Dahlbergh, was built around the town. The new defenses were among the most powerful in Northern Europe.