Compared to other cities in Denmark, there are actually not many buildings left in Copenhagen that are older than 1728 (there are some, but not a lot). A fire in 1728 burned down a rather large part of the medieval part of Copenhagen and another big fire in 1795 destroyed a bit more of the old part of the city. In 1807, the British kindly bombarded Copenhagen and set it ablaze yet again (Denmark had chosen to be allied with France soooo). Copenhagen was a closed city surrounded by bastions and a moat up to the mid 1850s. From that point in time the bastions started to get pulled down and the moats filled in. The lake in Tivoli is actually a remnant of a tiny part of the moat that once surrounded Copenhagen. Copenhagen underwent a major transition from the mid 1980s up to the 2010s. The harbour that used to be surrounded by heavy industry is clean and pristine today and there is no industries left facing the harbour. Copenhagen has truly become a wonderful but very expensive city.