Inspired by the work of the first YMCA, Missionary Thomas Valentine Sullivan led the formation of the first US YMCA in Boston, on 29 December 1851. The US YMCAs brought about many great organizational programs, such as staff training and certification, which launched the field of professional development. It also established the first retirement fund for any major welfare organization, founded upon a donation from industrialist John D. Rockefeller. Today, the nation’s 2,400 YMCAs make the YMCA the largest not-for-profit community service organizations in America, working to meet the health and social service needs of 17.5 million men, women, and children in 10,000 communities.