135 East 52nd Street, 1912.

Constructed on land purchased with donations by a number of wealthy New York society women, the Young Women's Christian Association building was completed and dedicated in 1912. The building housed the national headquarters of the charity. The section of the building entered through 135 East 52nd Street was known as "the Annex;" it provided space for the National Board Training program and residences for its trainees. Affectionately known as as "600," it was the first building to be built in the United States solely for the use of a woman's movement. The National Board of the organization decided to sell the building (which they had received many previous offers for) in 1981. The building was demolished and redeveloped. The Y.W.C.A moved into a number of rented headquarters through the 1980s and 1990s, including a stint in the Empire State Building. Following a reorganization in 2003, they consolidated their activities into their Washington, D.C. office.