In advance of its official opening on 24 September, the National Museum of African American History and Culture (NMAAHC) in Washington, DC, held a special preview day for the press on 14 September. For most of the several hundred attendees, it was the first chance to look inside the 400,000-sq-ft building, designed by a consortium of firms helmed by David Adjaye and Philip Freelon.

Fulfilling an idea that dates back to the early 1900s, but has met political opposition along the way, the museum honors the achievements of African Americans while telling the 'unvarnished truth', in the phrasing of one curator, about their oppression. The new museum was given the last buildable spot on the National Mall, Washington’s monumental core.

At the preview, David Skorton, secretary of the Smithsonian, and Lonnie Bunch, the museum’s director, addressed a full-to-capacity house in the Oprah Winfrey Theater (the TV personality was a major donor). 'We felt it was crucial to craft a museum that would help America remember and confront its tortured racial past,' Bunch said. 'But, it also had to find the joy, the hope, the resiliency, the spirituality, that was embedded in this community. The goal was to find that tension.'

That tension plays out in the sequence of galleries. They begin underground, telling the story of slavery and struggle in dark, compressed spaces, and through exhibits such as a slave auction block, a slave cabin from South Carolina, and a shawl and hymnal that belonged to abolitionist Harriet Tubman. Switchbacking ramps and a twisting black staircase lead up to the building’s main lobby. Above this rise two more gallery levels celebrating African American culture and institutions. Here, visitors can see Chuck Berry’s cherry-red Cadillac and Muhammad Ali’s boxing gear, or explore work by black visual artists.

Wrapping the upper levels is the filigreed 'corona', the signature design element of the museum, its form inspired by the tiered crowns found in Yoruban sculpture. The corona is composed of more than 3,000 aluminum panels with a PVDF coating, and it received close attention from the architects, as well as Washington’s powerful design-review boards.

'I was obsessed with this detail,' Adjaye says. '[The coating] is the same luminosity as bronze. It reflects and absorbs light exactly the way bronze does.' On the highly symbolic national landscape of the Mall, Adjaye says, there was no option but to get it just right. 'There was an understanding that this was in the nation’s capital, it was going to be looked at by everyone and it had to be perfect.'

President Obama (who gets his own exhibit case inside) will make a dedication to the museum on the opening weekend, and The Roots and other acts will play at a free music festival. Public interest is high: passes were snapped up so quickly that the museum extended its hours and issued more. Clearly, says Freelon, 'there was a pent-up demand for this sort of cultural institution on a national scale'.