More than 2.5 million people will pack the New York streets today to cheer on 50,000 marathon participants from around the world. <br/><br/>The city is heavily bolstering security for the race, parking more sand trucks to prevent vehicle attacks, stationing extra police on rooftops and deploying more anti-sniper units. <br/><br/>In addition to uniformed officers along the route, plainclothes officers will blend in with the spectators. Today's marathon will serve as a means for New Yorkers to come together in defiance in the aftermath of the latest<br/>attack to strike America's most populous city. <br/><br/>The race that takes runners through all five boroughs and culminates at Manhattan's iconic Central Park will be a show of "resilience" for a city recovering from tragedy.