In this photo provided by The Daily Free Press and Kenshin Okubo, people react to an explosion at the 2013 Boston Marathon in Boston, Monday, April 15, 2013. (Photo by Kenshin Okubo/AP Photo/The Daily Free Press)

P.S. All pictures are presented in high resolution.

Mounted cop in action on Tremont Street in Boston, Massachusetts, 1920 – 1929 (approximate). (Photo by Leslie Jones)

Runners cross the Verrazano-Narrows Bridge shortly after the start of the New York City Marathon in New York, November 2, 2014. (Photo by Lucas Jackson/Reuters)

The Revere Hotel in Boston, Ma. celebrated its grand opening on April 18 with a vertical fashion show. The Boston Rock Gym provided the models who rappelled down the exterior of the 24-story hotel wearing outfits created by the students from the Massachusetts College of Arts and Design and by Ted Baker London.

Photo: A model walks down the side of Revere Hotel in Boston during a vertical fashion show for the Massachusetts College of Art and Design on April 18, 2012. (Photo by Dominick Reuter/EPA/Lauren Fish/Lauren Frohne/Globe photo)

This combination of April 15, 2013 and April 2, 2014 photos show a police officer clearing Boylston Street following a bomb blast near the finish line of the 2013 Boston Marathon, and pedestrians crossing at the same corner nearly a year later in Boston. (Photo by Charles Krupa/AP Photo)

Competitors take to the streets of the capital in fabulous fancy dress costumes during the Virgin London Marathon 2012 on April 22, 2012 in London, England. (Photo by Mirror.co.uk)

A woman leaves sauna during the sauna marathon in Otepaa, Estonia on February 2, 2019. Participants have to track down, locate and visit designated saunas in the Otepaa area as fast as possible during the event. The team that completed all of the saunas in the shortest time wins. (Photo by Ints Kalnins/Reuters)

Portuguese runner Adriele Silva gestures during the Great Wall Marathon at the Huangyaguan section of the Great Wall of China, in Jixian of Tianjin, China May 19, 2018. (Photo by Jason Lee/Reuters)