Former President Joe ... the 60th Presidential Inauguration in the Rotunda of the U.S. Capitol in Washington, Jan. 20. [AP/YONHAP] Donald Trump took office as the United States' 47th president ...

And now two such letters from the past — Bill Clinton to George ... in Washington, D.C. on Thursday, just one day before he will be sworn in as the 45th president of the United States of America.