At last year's marathon, terrorists exploded two bombs, killing three people.
The Boston Marathon, which begins for most runners at 10 a.m., is the oldest marathon in the world and is held every year on Patriot's Day, a Massachusetts state holiday. Marathon officials expect 36,000 people, 9,000 more than last year to run in the race.
The city has ramped up security in preparation for the marathon. There will be 3,500 officers patrolling the streets, 100 more security cameras and bomb-sniffing dogs, according to CNN. Backpacks and handbags are banned for runners, and the Boston Athletic Association has asked spectators to not bring them.
Last year's tragedy has not deterred people from Westchester in running in this year's marathon. Almost every municipality, from Yonkers (seven runners) to Somers (one runner) will be running in Boston.
Yonkers resident Bette Clark is running her fifth marathon this year. Clark, who was in Boston for the marathon last year, said she wants to run as a tribute to the city. Clark, who did not run in 2013, said she would've been crossing the finish line at the time of the explosion.
"Last year was very emotional for the running community. So, I decided if I was in shape to run, I would," Clark said.
Hartsdale's Brian Wilantowicz ran the marathon last year, crossing the finish line an hour before the explosions.
Wilantowicz said he expects runners will have a lot on their mind this year.
"It is hard to articulate what I am feeling," Wilantowicz said. "I am just looking forward to getting back to Boston and running again. Of course I want to do well, but it is also going to be an emotional day."
John Reumann of Croton had finished the marathon and was eating lunch with his family when the explosion occurred. He vowed to his children he'd be back next year.
"We'll keep running, we can't be stopped," Reumann said. We're not going to stay away because a couple of crazy people made a big mess. This event is bigger than terrorism."
To view the event live, visit http://watchlive.baa.org/.
Brian Donnelly, Suzanne Samin and Danny Lopriore contributed to this report.
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