Cover sent from Tte. Matienzo Antarctic station to New York on 8/SE/1974, and returned to sender in Buenos Aires on 7/AU/1975 due to 'Addressee unknown'
Antarctic Campaign 1967/68: 5 covers cacheted "Grupo Naval de Tareas Antárticas" with postmarks of Antartic stations: Petrel, Belgrano, Brown, Esperanza and Orcadas, very nice!