A burned-out souvenir truck that sparked a security alert at the White House is pictured in Washington March 7, 2015. The security alert happened just moments before President Barack Obama and his family had been due to board a helicopter from the presidential mansion's South Lawn for Andrews Air Force Base. Obama and his family left the White House by motorcade instead of helicopter an hour later and boarded Air Force One at Andrews Air Force Base. REUTERS/Justin Mitchell (UNITED STATES)