Marines, also known as naval infantry, are military personnel trained to operate on both land and sea, with a specific focus on amphibious warfare—meaning they specialize in operations that involve landing on and securing coastal areas from the sea. Historically, marines have been responsible for raiding ashore to support naval objectives, boarding enemy ships during combat, and maintaining security and order aboard naval vessels. In modern times, marines still perform these traditional roles but have also expanded their duties to include rapid-response operations, humanitarian aid, disaster relief, special operations, and counter-terrorism. Marines typically deploy from warships using boats, landing craft, amphibious vehicles, or helicopters and can operate inland as far as their ship-borne logistics allow. The organization of marines varies by country. In many nations, marines are part of the navy, such as the United Kingdom's Royal Marines or Russia's Naval Infantry. In some countries, they operate under the land army, like the French Troupes de Marine. In rarer instances, marine forces are independent military branches, as in the United States Marine Corps (USMC). Specifically, the United States Marine Corps is a premier crisis response force within the U.S. Department of Defense. It conducts expeditionary and amphibious operations using combined arms, including infantry, artillery, aviation, and special operations forces. Founded in 1775, the USMC has a long history of amphibious warfare and expeditionary missions, operating both on land and from naval vessels. The Corps is known for its elite fighting capabilities and rapid deployment readiness. In simple terms, marines are elite forces trained to fight on the seas and shores, bridging the gap between naval operations and ground combat, often tasked with the first wave of assaults from the sea onto hostile or contested land.