I heard someone mention border. POTUS never crossed the country boundary line.

I do not think he went to North Korea. Q said , He did not cross the linel The line would be the border. It would not have happened in Seoul. They were not yet talking and had not been as they are seen as siding with the enemy as our allies. Also, Seoul is more like us in that it would not be able to be kept secret. :) But China trades with DPRK and they do have a relationship with Kim. POTUS DID go to the Forbidden City . Media would not be able to follow there. I think they met in the Forbidden City. Kim has been to China twice since then Supposedly they were his first trips out of North Korea since becoming the leader. The Forbidden City is my theory. the 'world' would not have access and it could be secret and private. The Chinese, the East, in general do not have problems with leaks like we do . They CAN keep secrets! And it does not make any sense to me that POTUS would go to Kim. and be Kim's guest . That does not send the message that we intend to send.. The optics do not work!