Bystanders cover their faces against the smoke as they watch the scene of an explosion and building collapse at Park Avenue and East 116th Street March 12, 2014 in the Harlem section of New York. A gas leak was responsible for a major explosion that destroyed two buildings in Manhattan on Wednesday, killing two people and injuring 18 others, New York Mayor Bill de Blasio said. "Today at approximately 9:30 am, there was a major explosion that destroyed two buildings, the explosion was based on a gas leak," de Blasio told reporters at the scene.    AFP PHOTO/Stan HONDA        (Photo credit should read STAN HONDA/AFP via Getty Images)