Worn to commemorate the victims of the Boston Marathon bombing. The bombing was a domestic terrorist attack that took pl...ace during the annual Boston Marathon on April 15, 2013. Brothers Dzhokhar and Tamerlan Tsarnaev planted two homemade pressure cooker bombs, which detonated near the finish line of the race 14 seconds and 210 yards (190 m) apart. Three people were killed and hundreds injured, including 17 who lost limbs.