Changing of The Guard Ceremony - Tomb of the Unknown Soldier

a formal ceremony in which sentries providing ceremonial guard duties at important institutions are relieved by a new batch of sentries.The guard is changed every hour on the hour Oct. 1 to March 31 in an elaborate ritual. From April 1 through September 30, there are more than double the opportunities to view the change because another change is added on the half hour and the cemetery closing time moves from 5 to 7 p.m.