Invercargill couple Barry and Shirley Keen left this month to visit the United Nations headquarters in New York City.
It is Mrs Keen's second visit in the past 12 months.
Mrs Keen's lifelong penfriend Ban Ki Moon is the UN secretary-general.
In 1962 Mr Ban, a Korean, and teenager Shirley McNicol, from Southland's junior Red Cross at Southland Girls' High school, represented their countries at an American Red Cross Operation.
They struck up a friendship that has endured more than half a century, during which they graduated, married and became parents and grandparents, sharing anecdotes and family photos.
Mrs Keen remembered the teenage Korean boy saying he “wanted to make a difference" when the group shared ambitions.
Last year, at his invitation, she visited the Ban family and learned of plans for this 50th reunion, which brings together 40 of the former students from Lebanon, Poland, Belgium, India and Japan. Mrs Keen has exchanged letters with several.
Mr and Mrs Keen will fly to Washington and make a special visit to the White House.
They will visit the Goddard Space Centre and attend a dinner hosted by Mr Ban at the Korean Embassy. They will travel to New York, where Mr Ban hosts a dinner at the United Nations, and the next day introduces them to New Zealand UN representatives.
- The Southland Times