The United States Marine Corps (also known as USMC) is one of the five branches of the military of the United States in the United States Department of Defense. It was created in 1775 as a special maritime service. Samuel Nicholas founded it. He was the first commissioned officer in the Corps. The birthplace of the Marines is in Philadelphia at the Tun Taven. Although it is part of the U.S. Naval Service, it is a separate military branch with its own special ranking structure. It also has its own Naval Aviation
The Marines have been involved in many conflicts, and had important roles in key battles such as Tripoli, Iwo Jima, Guadalcanal, and Inchon Bay. Every Marine receives infantry training to be ready for battle at all times. Marine Corps training is also known for being especially challenging; at 13 weeks long, Marine Recruit Training is the longest basic training of the five military branches. United States Marines place a large emphasis on morale. This is reflected in their motto, semper fidelis (meaning "always faithful").