One year ago today, the DPRK-U.S. summit in Hanoi -- the second such meeting between the leaders of the two countries -- fell apart in acrimony.

Following months of high hopes that Pyongyang and Washington would be able to build on the sparse agreement made the previous year in Singapore, President Donald Trump emerged after hours of talks with Kim Jong Un to announce that the U.S. had decided to walk away. The North Koreans, he said, had asked for "all the sanctions" to be lifted -- a price the U.S. was simply not willing to pay.