Boston observed a moment of silence at 2:50 pm (1850 GMT) Monday in honor of the three people killed and 180 wounded in the twin bombing of the city's marathon exactly one week ago.
President Barack Obama also observed the moment of silence, as did traders at the New York York Stock Exchange.
Hundreds gathered outside the security cordon set up near the blast sites at the marathon finish line on Boylston Street to honor the dead and wounded. Some prayed while others silently took video footage of the occasion.
Some left flowers tied together with purple or white ribbons at a makeshift memorial on the corner of Boylston and Berkeley Streets.