Meetings between Former US President Donald Trump and North Korean leader Kim Jong-Un's have been one of the highlighting events during Trump's presidency that drew global attention.
Recently, some interesting revelations, regarding these meetings, have been made in the third and final episode of a new BBC series Trump Takes On the World, directed by Tim Stirzaker.
New details about how these summits came about as BBC spoke to those who were in the room when the two men met.
What they saw stunned even the most seasoned diplomats - not least when Trump offered the North Korean dictator a lift home on Air Force One.
Matthew Pottinger, the top Asia expert on Trump's National Security Council told us: "President Trump offered Kim a lift home on Air Force One. The president knew that Kim had arrived on a multi-day train ride through China into Hanoi and the president said: 'I can get you home in two hours if you want.' Kim declined."
The offer of a ride home was one of many surprises in an unlikely bromance between the two men that started in Singapore when, as former National Security Adviser John Bolton told us: "Trump thought he had a new best friend."
Here, Trump made another gesture that shocked his own team, when he agreed to Kim's request to cancel joint military exercises between the US and South Korea.
Bolton told the BBC: "Kim Jong-un, as he had many times in the past, complained about the big joint exercises between South Korea and American forces, which had been going on on the Korean peninsula for about 60 years plus.
"Trump, out of nowhere, said, 'I'm going to cancel the war games [as he called them]. There's no need for them, they're expensive and it will make you happy.' I couldn't believe it.
"[Secretary of State] Pompeo, [Chief of Staff] Kelly and I were sitting there in the room with Trump and we weren't consulted. It came simply from Trump's own mind. It was an unforced error; it was a concession for which we got nothing in return."
The fact that the meeting happened at all was a surprise to many.
Moreover, top UN official Jeff Feltman describes how, at the height of the crisis, he delivered a secret message from Trump to Kim that offered a meeting.
UN Under-Secretary General for Political Affairs Feltman had been invited to Pyongyang by the North Koreans - but the US State Department had told him that they didn't think it was a good idea for him to go. However, a few weeks later, UN Secretary General Antonio Guterres visited the White House.
Feltman told us: "They were comparing notes on what was happening, what might be possible, how dangerous was it, how likely would a military response be, all that sort of thing. And Secretary General Guterres said to President Trump: 'Jeff Feltman has this strange invitation to go to Pyongyang and lead a policy dialogue with the North Koreans.'
"And Trump leaned over toward him and said: 'Jeff Feltman should go to Pyongyang and Jeff Feltman should tell the North Koreans I'm willing to sit down with Kim Jong-Un.'"