A group of Americans in Paris agreed in 1866 that the country needed a great museum; the Met was incorporated in 1870 and opened in a Fifth Avenue ballroom with 174 paintings. It moved to Central Park in 1880, and the Beaux-Arts facade everyone pictures was added by Richard Morris Hunt's firm in 1902. Unfinished stone blocks are still visible above the paired columns. The Temple of Dendur was given by Egypt in 1965 for American help saving monuments from the Aswan dam.
Source: The Metropolitan Museum of Art, official museum history; The Metropolitan Museum of Art, institutional architectural history of the Fifth Avenue facade and Great Hall; The Metropolitan Museum of Art, Temple of Dendur collection record and acquisition history