Two Marines use a fire hose to wash the underside of a Humvee on a wash rack at the port facility in Paldiski, Estonia, on July 17, 1997, during Exercise Baltic Challenge 97. All mud and dirt must be washed from the Humvee before it is reloaded onto the Maritime Prepositioning Ship S.S. Sgt. Matej Kocak anchored off shore. Baltic Challenge '97 is a multinational exercise conducted as a NATO Partnership for Peace initiative involving more than 2,600 military personnel from Denmark, Estonia, Finland, Latvia, Lithuania, Norway, Sweden, and the U.S. The focus of the training is peacekeeping tasks and humanitarian assistance operations.