The McMurdo Station is a United States Antarctic research center on the south tip of Ross Island, which is in the New Zealand-claimed Ross Dependency on the shore of McMurdo Sound in Antarctica. It is operated by the United States through the United States Antarctic Program, a branch of the National Science Foundation. The station is the largest community in Antarctica, capable of supporting up to 1,258 residents, and serves as one of three United States Antarctic science facilities. All personnel and cargo going to or coming from Amundsen–Scott South Pole Station first pass through McMurdo. All US mail from Antarctica is processed by United States Air Force, and you can see on postmark military postcode APO AP 96599. And of course, standard US stamps are used, Greetings from South Carolina, issued on 4.4.2002, and Year of the Rooster, issued on 30.12.1992.
Thank you so much, Li Ming, for this great surprise!