article_snippet.sent: Due to Greystone Park extremely large size, Greystone Park was once the largest building in the US, but was surpassed by the Pentagon .
article_snippet.sent: The interior of the largest building in the US has been left to decay so badly, with windows and roofing blown out, The interior of the building would be too expensive to restore The interior of the building .
article_snippet.sent: But campaigners claim the largest building in the US contains a lot of elements of history that should be preserved not destroyed .
article_snippet.sent: the largest building in the US was widely said to be the largest by footprint in the U.S. until 1943, when the largest building in the US was surpassed by the Pentagon - which has 6.5million square feet altogether.
article_snippet.sent: A chair (left) shows visible signs of rust and decay, while the inside of the largest building in the US has become known for the inside of the building holes in the ceilings (right) the largest building in the US opened in 1876 and expanded to treat more than 7,000 patients in the 120 years the largest building in the US was open for before closing in 2003 .