Starting today, you'll be seeing up to 500 new 2018 Boston Marathon banners flying from light posts in the city, a signal that the big race is right around the corner.

Mayor Marty Walsh joined four-time Boston Marathon winner Bill Rodgers and other top American runners in Copley Square Monday to reveal the new banners, which carry the slogan "Together Forward." Rodgers says the hoisting of the banners is the symbolic beginning of Boston's marathon season.

"There are other marathons that may be bigger, but ours is the oldest and has so much history," he said. 

Walsh used the occasion to note that for the fourth consecutive year, April 15, the day before the race, will be recognized as One Boston Day — a day of service for the people of Boston that was started in 2015 to honor the city's resilience and strength in the wake of the 2013 marathon bombings. City employees will spend the week leading up to that day volunteering in neighborhoods around Boston and collecting new and lightly used sneakers for those in need.

"I'm asking everyone who loves this city to join the One Boston movement," said the mayor.

This year will mark the fifth anniversary of the marathon bombings. During the bombings and their aftermath, four people were killed — including three spectators and one MIT police officer — and more than 200 were injured. Rodgers says he hopes the marathon will not always be defined by this tragedy. 

"We runners all get along, and that's what the marathon symbolizes," he said.