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)

A statue of a man sleepwalking in his underpants is surrounded by snow on the campus of Wellesley College, in Wellesley, Mass., Wednesday, February 5, 2014. The sculpture entitled “Sleepwalker” is part of an exhibit by sculptor Tony Matelli at the college's Davis Museum. (Photo by Steven Senne/AP Photo)

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)

Participants run at the “Half-Naked Marathon” at Olympic Forest park in Beijing, China, February 28, 2016. This annual running event which requires participants to run half-naked, was organized to promote environmentally friendly lifestyles. (Photo by Kim Kyung-Hoon/Reuters)

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)