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.
The oldest building would be the cathedral built between 1628 and 1633 although the city walls were built between 1613-1618 and are still standing and complete