Tight security is in place as participants including a handful of New Zealanders get ready for the Boston Marathon, a year after a deadly terrorist attack.
Three people were killed and 264 injured when two home-made pressure-cooker bombs exploded near the finish line on 15 April 2013, sending metal fragments flying through the crowd.
Nineteen New Zealanders are among the 36,000 people taking part this year, the second-largest field in the race's 118-year history. They will set out from a town west of the city for the 42km race that finishes on Boston's Boylston Street.
Wellington property manager Andrew Wharton ran in the marathon last year and felt it was important for him to return to the city despite the bombing.
"All that we witnessed was just so horrific, I didn't want my memories of the greatest sporting moment of my life to be one of horror and fear. I just decided within a month of getting home that if I was going to go back I had to go back the next year."
Mr Wharton said there is heightened security presence and armed police are around the city.
Last week, ceremonies were held in Boston to commemorate victims and survivors of the bombing. Vice-President Joe Biden led tributes at the the 15 April services attended by representatives from families of the victims, members of the city's fire, police and ambulance services, government agencies and civic organisations.
Relatives of university police officer Sean Collier, who was killed during a manhunt for the suspects, also attended. Several survivors spoke at the event, including Patrick Downes and dancer Adrianne Haslet-Davis, both of whom lost their lower left legs in the bombings.
Bombing suspect Dzhokhar Tsarnaev, 20, is due to stand trial in November. Prosecutors allege that he set off two pressure cooker bombs with his older brother Tamerlan, 26, who later died in a police shoot-out. He has pleaded not guilty.