The museum's space will be doubled to include new galleries, a study centre and temporary-exhibition and education spaces.
The museum has gradually grown since it was founded in 1870, causing pressure on existing facilities. The practice claims the masterplan will 'transform the experience' of about a million visitors a year, offering exhibitions, lectures, films and events.
Foster plans to reinforce the Beaux-Arts plan of the museum, designed by Guy Lowell in 1907; a 'crystal spine' will reintroduce circulation on the north-south axis, creating a glazed courtyard at the centre aiming to orientate visitors on their arrival.
The practice hopes to establish 'a creative dialogue between the old and the new' - 'continuing the language of the Reichstag in Berlin and the Great Court of the British Museum'. Emphasis has also been placed on energy efficiency.
Landscaping will connect the museum with the adjacent Back Bay Fens, originally designed by Frederick Law Olmsted, designer of New York's Central Park.
by Will Hunter