Complex sentence: The City of New York used its power of eminent domain and designated the building as a park, a designation which was rescinded when the title was acquired by the Sons of the Revolution in the State of New York in 1904.
Split into simpler sentences: The City of New York used its power of eminent domain and designated the building as a park. This designation was rescinded when the title was acquired by the Sons of the Revolution in the State of New York in 1904.