that's where all the ambulances were coming from that day, so that's the one thing that sets you off a little bit, when the next time you see an ambulance and loud noises coming down that street, you certainly have flashbacks. >> reporter: the city was violated and on a day the locals regard with no small amount of pride. >> it hurt us. it hurt patriots day. >> reporter: the boston marathon is run on patriots day a civic holiday here that people say is the best day of the year in boston. if you're not at the marathon, then you're at the red sox game that starts at 11:00 in the morning. it's a party. it's spring, and it's a holiday unique to boston because of what happened here april 19th, 1775. it begins at the old north church, one if by land, two if by sea. paul revere's ride to warn the militias in lexington and concord that the british were on their way. a battle immortalized in