James Arness, the actor best known for his portrayal of U.S. Marshall Matt Dillon in the long-running TV series Gunsmoke, was the first WWII American soldier to jump off his boat at the Anzio beachhead. He was ordered by his commander to do so because, standing at 6' 8" in height, he was the tallest man in his company, and the water's depth needed to be tested as a safety precaution.