If given a choice, I always prefer to hide "real" caches. There is always a good feeling you get by leaving something behind in an unique location for others to find. Antarctica is a pretty neat and unique place to hide a cache and to this date there have only been a few placed on the continent. But while geocaching, one must respect the local laws and if that means that you may not take or leave anything of any type from the Australian claim of Antarctica, then you must find an alternative. I would of loved to placed a container somewhere near Mawson station, but since I cannot, this has to be a virtual cache with a surprise element.
The coordinates above will lead you to a location near the centre of the station where you'll find a number of flags plus a post with directions and distances to various cities around the world. To score a "find" for this cache you must have your GPS with you, a camera, plus a friend to take at least two pictures of you.
Picture #1: At the directional post, have your friend take your picture with you holding your GPS in one hand and your other hand pointing to a city on the signpost that most closely represents where you live. Alternatively, you may make your own sign out of cardboard and write your home city and distance from this post to it. This is the easy portion of the cache find. Picture #2: The surprise element and the harder portion of the cache find. Without leaving the confines of the station, your second picture must be of one or more of the animals (penguins, seals, etc) that live around the station boundaries. This picture must include the animal, yourself, and your GPS and all three must be all clearly visible. Please respect the station's guidelines for approach distances to wild animals and do not exceed them to obtain this second picture. The surprise is what you will find for wildlife and where you'll find it, so if you have to wonder around to find the ideal picture, then go right ahead! When you have completed your cache find, you may use one of the two communal computers available on the station to post your find and upload your pictures.