Plymouth Church merged with the Congregational Church of the Pilgrims in 1934, and the resulting combined congregation was named "Plymouth Church of the Pilgrims". The Congregational Church of the Pilgrims left its Richard Upjohn-designed church building, which later was designated a New York City Landmark as Our Lady of Lebanon Maronite Catholic Church. The building's stained-glass windows, including windows by Louis Comfort Tiffany and Tiffany Studios, were moved to Plymouth Church's nearby Hillis Hall. The church also displays a piece of Plymouth Rock, from the traditional landing site of the "Mayflower" Pilgrims.