Each branch of the U.S. military (Army, Marines, Navy, Air Force, and Coast Guard) has their own honor guard, which serves to enhance the decorum at official military events and may sometimes also be seen as "guardians of the colors" due to their role in displaying flags at state ceremonies.
Some time ago, the US Navy Presidential Ceremonial Honor Guard (established in 1935) was invited to Norway to display their prowess and take part in an international competition. The competition featured some of the best groups from around the world and throughout the NATO nations. Once it was time for our boys to show their mettle, however, it was clear who the best unit was.
Honor guards recruit their members from volunteers who are very carefully screened for their physical ability, dexterity, motivation, and discipline. Only the best are chosen to join honor guards - it is a duty that carries immense weight, considering that these are the men and women who give final honors to the soldiers we have lost.
H/T: Walter Tan