The Boston Marathon is set to be a sombre affair this year as people remember the tragic aftermath of last year's race. On Monday April 15th 2013, there were two explosions near the finish line of the race, killing three and injuring 264. This year's marathon, taking place on Monday 21st April, will mark the 118th run and ahead of the event, comfort dogs have arrived in the city. Their arrival marks the fourth time that the comfort dogs, funded by donations, have headed to Boston in the past year to work with marathon survivors and their families. The comfort dogs project was started with just four pups in 2008 following the Northern Illinois University shooting and is now a project in dozens of states. The comfort dogs have helped to bring solace to people Last year several golden retrievers were dispatched to the city shortly after the bombings, and were placed at the church and local hospitals. "Dogs just bring a wonderful comfort," Tim Hetzner, president of LCC K-9 Comfort Dogs, told Yahoo News. "They're a calming presence and allow victims to open up and talk about what happened -- which is a critical part of the healing process." Images via Lutheran Church Charities