This museum may be the last important building on the mall. It will occupy a five-acre plot near the Washington Monument and the National Museum of American History. It is one of the last open spaces on the Mall, and the museum's founders have specified that the building must respect the history and visage of the monument. 

Officials with the Smithsonian, which will oversee the details of construction and exhibition content, said they didn't expect the building to be very tall, but it would cover 300,000 to 350,000 square feet.

The museum is in the private phase of a fundraising campaign. The project is expected to cost $500 million, with half funded by Congress.