2. Christian Jacobs, 4, of Hertford, NC, lies on the grave of his father, Christian James Jacob, during Memorial Day celebrations at Arlington National Cemetery in Arlington, Virginia May 25, 2015. REUTERS/Joshua Ro

3. A veteran stands to take a photo during a Memorial Day ceremony at the Intrepid Sea, Air & Space Museum in the Manhattan borough New York May 25, 2015. REUTERS/Carlo Allegri

4. Navy Vietnam War veteran Dennis McClelland of Murrells Inlet, South Carolina, holds a U.S. flag during a Veterans March on Ocean Boulevard in honor of Memorial Day in Myrtle Beach, South Carolina, May 25, 2015. REUTERS/Randall Hill

5. A soldier sits in front of a grave during Memorial Day celebrations at Fort Bliss in El Paso, Texas, May 25, 2015. REUTERS/Jose Luis Gonzalez

6. WWII Veteran and D-Day survivor Frederick Carrier takes notes during a Memorial Day ceremony at the Intrepid Sea, Air & Space Museum in the Manhattan borough New York May 25, 2015. REUTERS/Carlo Allegri 5 /

7. A U.S. serviceman holds up a U.S. flag during a Memorial Day ceremony at the Intrepid Sea, Air & Space Museum in the Manhattan borough New York May 25, 2015. REUTERS/Carlo Allegri

8. A member of an honor guard holds his rifle as the motorcade carrying U.S. President Barack Obama departs after he participated the Memorial Day observance at Arlington National Cemetery in Arlington, Virginia May 25, 2015. REUTERS/Jonathan Ernst

9. People stand for the national anthem during the Memorial Day observance at Arlington National Cemetery in Arlington, Virginia May 25, 2015. REUTERS/Jonathan Ernst

10. A woman walks past graves during Memorial Day celebrations at Arlington National Cemetery in Arlington, Virginia May 25, 2015. REUTERS/Joshua Roberts

11. A memorial wreath that New York Mayor Bill de Blasio threw into the Hudson River floats during a Memorial Day ceremony at the Intrepid Sea, Air & Space Museum in the Manhattan borough New York May 25, 2015. REUTERS/Carlo Allegri

12. A child holds onto the U.S. flag as it is rolled up during a Memorial Day ceremony at the Intrepid Sea, Air & Space Museum in the Manhattan borough New York May 25, 2015. REUTERS/Carlo Allegri

13. People sit under umbrellas with the United States flag during Memorial Day at Arlington National Cemetery in Arlington, Virginia May 25, 2015. REUTERS/Joshua Roberts

14. People stand for the playing of taps during the Memorial Day observance at Arlington National Cemetery in Arlington, Virginia May 25, 2015. REUTERS/Jonathan Ernst

15. A Secret Service counter-assault team member (top R) keeps watch from the roof of the amphitheater as U.S. President Barack Obama participates in the Memorial Day observance at Arlington National Cemetery in Arlington, Virginia May 25, 2015. REUTERS/Jonathan Ernst

16. President Barack Obama and U.S. Army Military District of Washington Commanding General Jeffrey Buchanan participate in the wreath-laying ceremony at the Tomb of the Unknown Soldier as part of the Memorial Day observance at Arlington National Cemetery in Arlington, Virginia May 25, 2015. REUTERS/Jonathan Er

17. Ryan Buckingham of Camdenton, Missouri, touches the grave of his friend David Hortman during Memorial Day at Arlington National Cemetery in Arlington, Virginia May 25, 2015. REUTERS/Joshua Roberts

18. Christian Jacobs, 4, of Hertford, NC, walks with his mother, Brittany, during Memorial Day celebrations at Arlington National Cemetery in Arlington, Virginia May 25, 2015. REUTERS/Joshua Roberts

19. General John Kelly of the United States Marine Corps speaks during a Memorial Day ceremony at the Intrepid Sea, Air & Space Museum in the Manhattan borough New York May 25, 2015. REUTERS/Carlo Allegri