U.S. Marines with 1st Battalion, 1st Marine Regiment,

U.S. Marines with 1st Battalion, 1st Marine Regiment, defend their position after a simulated attack at Shoalwater Bay, Queensland, Australia, May 29, 2016. The simulated attack, part of Exercise Southern Jackaroo, increased proficiency in defensive actions against an oncoming enemy force during Marine Rotational Force – Darwin (MRF-D). MRF-D is a six-month deployment of Marines into Darwin, Australia, where they will conduct exercises and train with the Australian Defence Forces, strengthening the U.S.-Australia alliance. (U. S. Marine Corps Photo by MCIPAC Combat Camera Lance Cpl. Osvaldo L. Ortega III/Released)