In 1908, the progressive National Child Labor Committee hired Lewis Hine, a New York sociologist and photographer, to document the exploitative working conditions of child laborers in dozens of occupations, from mining and manufacturing to farming and newspaper selling.

Hine crisscrossed the country over the course of a decade, sneaking around employers to photograph and interview children about their hours, compensation and general treatment.

Among the many workers he captured were bicycle messengers in several southern cities.

Most of the messengers worked for telegraph companies or drug stores and spent exhaustingly long hours making deliveries. In his interview notes, Hine expressed a particular concern about the children’s exposure to danger and vice — many of the youngsters’ assignments took them into red light districts rife with drug dealers and sex workers.

The photos that Hine took became the face of the child labor reform movement and ultimately helped push through the 1916 passage of the Keatings-Owen Act, which set age and shift length restrictions for young workers. While the act was struck down by the Supreme Court, it set the stage for lasting reform to be created during the New Deal of the 1930s.