Earliest Known Photo of the Boston Marathon in 1904

The Boston Marathon is an annual marathon hosted by several cities in Greater
Boston in eastern Massachusetts. It is always held on Patriots’ Day, the third
Monday of April. The first annual event was held in 1897, inspired by the
success of the first modern-day marathon competition in the 1896 Summer
Olympics. The Boston Marathon is the world’s oldest annual marathon, and
ranks as one of the world’s best-known road racing events. It is one of six
World Marathon Majors. The Boston Athletic Association (B.A.A.) has
managed the marathon since its inception.

The widely viewed event attracts about 500,000 spectators each year. The
Centennial Boston Marathon in 1996 established a record as the world’s
largest marathon with 38,708 entrants, 36,748 starters, and 35,868 who 
crossed the finish line. This years marathon was marred by tragedy when
two bombs were exploded near the finish line, killing 3 people and injuring
more than 170.