The United Nations Postal Administration (UNPA) is the postal agency of the United Nations. It issues postage stamps and postal stationery, denominated in United States dollars for the United Nations offices in New York, in Swiss francs for the offices in Geneva and in euros (formerly schillings) for the offices in Vienna. Postage rates charged are identical to those of the host nation. Only United Nations stamps in the appropriate currency may be used at a given United Nations office. In practice, however, most UN agencies use meters, and the stamps are most often used by tourists and collectors.
This perfectly postmarked cover from UN Geneva Post office sent by my good friend Jan wittmack from Germany. He is a thematic philatelist too. The letter posted on Aug 15, 2013 and I received on August 23, 2013. Thank You Jan for the nice cover from UN Geneva Post office.