The Boston Marathon is considered a unicorn among distance running races globally and the oldest marathon in the world. Runners are required to qualify for the race by meeting time standards for their age group and gender and then apply to be accepted via a lottery system. The race, which occurs on the third Monday in April each year, generally involves between 20,000 to 26,000 runners based on data from Boston Athletic Association, the organization that has hosted this race for over 100 years.
