The Grand Duke received in audience at the GDP Dr. Bertrand Piccard. Dr. Piccard is a psychiatrist, aeronaut, lecturer, and president of the charitable foundation "Winds of Hope." He is also a roving ambassador for the United Nations. He was in Luxembourg for a conference on Innovation for sustainable performance.
It's just my opinion but he sounds like a pretty impressive guy. You know, the kind of guy who has lunches with a Grand Duke. ;) He has his own website which details his apparent awesomeness a little more.
Here is the website of Winds of Hope. Again, I'm impressed by their mission and success. It's an admirable cause. I warn you in advance if you chose to visit website that the images are graphic and involve children. If you're super sensitive you'll want to skip this part. I just wanted to provide a little info about what this man does.