Thousands joined the inaugural 9/11 Memorial 5K Run/Walk on Sunday, despite increased police security. The route started out at Pier 57 and wound around Lower Manhattan. From dedicated athletes to families with kids in tow, participants turned out to honor the victims and the first responders that poured into the area after the attacks. April 21 is the anniversary of the date that President Obama signed the law officially decreeing Sept. 11 to be a day of service and remembrance. Runners also paid tribute to Boston, wearing “I Run For Boston” t-shirts and pinning messages or black ribbons to their shirts. Security was tightened around the race following the April 15 bombing of the Boston Marathon. Following the race, visitors were invited to Family Day on Vesey St. between Church St. and Broadway to celebrate a sense of unity and the new generation of New Yorkers that will inherit it.