( CNN) This has been one hell of a year. As a historian who invests much of his time analyzing past changes of our current situation, I can say that this year has been one for the record books. The topsy-turvy world that President Trump has created in Washington has left many chiefs spinning. On a daily basis, it has been hard to know what will come next. From the tweets to the Russia investigation to the tax cut, 2017 was unbelievable.