(NBC NEWS) Mourners gathered Tuesday to remember the victims of the Boston Marathon bombings — and pay tribute to those who rushed to help them — a year after twin explosions ripped through the heart of the city.

The solemn day of remembrance started around 8 a.m., when Massachusetts Gov. Deval Patrick and Boston Mayor Marty Walsh laid wreaths in front of the bombing sites, with the families of the three people who died in the blasts — Krystle Campbell, Lingzi Lu, and Martin Richard — in attendance.

Boston Cardinal Sean O’Malley led a silent prayer in remembrance of the victims. Bagpipers played “Amazing Grace.” Jane and Henry Richard, brother and sister to Martin Richard — at 8 years old the youngest of those killed — laid a wreath at the race’s finish line. Jane lost a leg in the attack; Henry sustained shrapnel wounds.

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