MAA (military acronyms & abbreviations)
'(<a href="http://www.j-archive.com/media/2005-10-27_DJ_16.jpg" target="_blank">Cheryl of the Clue Crew gives the clue while standing in the ANZUS corridor of the Pentagon.</a>)  I'm in the Pentagon corridor that honors the Pacific security treaty known as ANZUS, an acronym for these three nations'
Australia, New Zealand, & the United States