Rome, April 15 - The powerful explosion from the bombs at the Boston Marathon Monday afternoon local time sounded like a cannon shot, long-time Italian marathon runner Salvatore Giansiracusa told ANSA. "Being from Rome, I thought it was the noon cannon (that goes off daily from Gianicolo Hill)...but I thought, what are they celebrating? Then I heard the second bang...it was terrifying," Giansiracusa said. Giansiracusa was one of 50 runners from the Italian 'Born to Run' organization who flew to Boston, Massachusetts for the annual race. After the second bomb detonated, Giansiracusa said that he saw "people running around a corner...then a woman fell to the ground. At that point I saw people fleeing and I knew what was going on".