[citation needed] Dr. Hagen was the first foreigner to trek throughout Nepal during geological and geographic survey work and mapping on behalf of the United Nations.

He filmed Nepalese cultural and ethnic diversity originally as produced as a silent documentary, and later with an English narration in his own voice.

[5] Hagen was a pioneer in the field of development aid, undertaking missions to the Himalayas, eastern Africa and South America in a career spanning over 60 years.

[7] Hagen retired from the UN in 1972, worked as a freelance adviser for organisations involved in foreign aid and later returned to the Federal Institute of Technology at Zurich where he lectured on the problems of the developing world.

Soon after the film was shown, he died in early 2003 at the age of 85 in his home in Lucerne[9] on Good Friday, three days after his wife,[10] Gertrud in Lenzerheide.