To those from the Western hemisphere, it’s always fascinating to hear that some homes and businesses from the times of the Greek philosophers still have inhabitants, and then you remember that the Western hemisphere is itself not without its own examples, for example some Mexican villages still have temples from the times of the Mayans.
not exactly “a” building, but i live around 20 minutes from a copper mine which was in active use from around 900AD to within my lifetime. it’s a museum today.