The Serbian Orthodox Cathedral of Saint Sava, at 16-20 West 26th Street between Fifth and Sixth Avenues in Manhattan is the largest Serbian Orthodox church outside of Serbia. The parish held its 60th anniversary at the end of last year, amid extensive restoration to its historic building.
Christopher Gray's "Streetscapes/The Serbian Orthodox Cathedral of St. Sava on 25th Street" provides a good overview of the church's history. The church was built in 1855 by the Episcopals as Trinity Chapel, and was joined in 1866 by a clergy house and in 1870 by a school building, all on the same site between 25th and 26th streets. The Serbian community purchased the buildings in 1943 and converted them for Orthodox use.