. ♪ >> it tells the story of her impact and also links her to other singers like miss denyce graves.rter: it will be rotated with the outfit anderson actually wore at the lincoln memorial. ironically it was graves donation that the gown given to her that helped the museum find the 1939 outfit. >> it's miraculous because i didn't think anything from that concert existed. holding the outfit she actually wore. >> reporter: graves seized the gift of the gown as a link to a legacy. and she knew she had to pass it like music. it doesn't belong to me. it passes through me. and i was charged to be the one to shepherd it to its rightful home. >> now, we expect denyce graves to be right there with many other big names for the grand opening of the museum set for september 24th. the president will cut the ribbon that day. and you can take a look mind the scenes of the museum in the nbc washington app. just search african-american museum. >>> so amazing to hear those two voices. i grew up with my mother talking about mary ann anderson and how important she was to america. >> yeah. great to see th