I would have to say 95-99 percent accurate! Even though we strive to be darned close, nothing can be 100 percent accurate with historical buildings! So many factors come into play when considering the details. There are probably many details that aren’t part of historical record, for instance. Some buildings were built before the advent of photography, so we may not know for that reason. Some areas may be private that only a handful of people could know the details about. And, lastly, there’s the fact that it can be nice to keep things somewhat within the realm of fantasy, without being too detailed. After all, it’s still just a LEGO playset!