Question

What is the changing of the guard?

Answer 1

That is a pretty broad thing.  There is a changing of the guard at Arlington national cemetery and other memorial places across the country.  They also do it in England at some of there important and historical sites.  It usually refers to a event that happens when the Soldiers who have been stationed at one of these sights are rotated out in a very ceremonial manner.  There are plenty of examples on youtube that you can look up.