From Mawson Research Station - the oldest of Australia's Antarctic research facilities. It was stamped and signed on the back by the Mawson OIC (officer in charge), Luc De Pauw. I also sent down a postcard to be postmarked. I was reading in Luc's blog that on the day that he did this for me, he had 400 other pieces of mail to process. Overall, a nice little souvenir from the Austrailian Antarctic Territory.