More than 15 years after it was first established, the National Museum of African American History and Culture opens on the National Mall on September 24, 2016. Barack Obama, the nation’s first African American president, leads the ceremony and officially opens the museum by ringing the Freedom Bell, a bell from an African American Baptist church founded in 1776.

As far back as 1915, there had been proposals for a museum recognizing the achievements of African Americans. In 1929, President Herbert Hoover approved a commission to create such an institution, but it never received funding. Various attempts were made to pass legislation establishing a museum through Congress, including multiple bills introduced by Georgia congressman and civil rights icon John Lewis, but even after the Board of Regents of the Smithsonian Institution joined the effort in the 1990s it still took more than a decade.

Finally, in 2003, Congress approved and President George W. Bush signed legislation allocating $17 million to plan the museum and choose a site. Eventually, it was decided that the museum would sit on the National Mall, the newest addition to what is literally a long line of museums stretching from the Washington Monument to the Capitol. The final design, however, was like nothing else in the area: an inverted step pyramid, encased in a bronze screen that references historic iron grilles from African American communities in Charleston, South Carolina and New Orleans, Louisiana. In the words of David Adjaye, a British architect of Ghanaian descent who was part of the design team, the building was meant to provide a “punch” at the end of the “row of palaces” that was the rest of the Mall. The building rises five stories into the air and reaches equally deep underground.

The museum was completed with just months left in Obama’s second term. At the opening ceremony, the president shed tears as he talked about watching the museum’s construction and imagining how he would one day tour it with his grandchildren. In addition to two former presidents, the Chief Justice of the Supreme Court and entertainers like Will Smith and Oprah Winfrey, Obama was joined by four generations of an African American family, the Bonners. 99-year-old Ruth Bonner, whose father was born into slavery, helped him ring the Freedom Bell along with her daughter, granddaughter and great-granddaughter. The NMAAHC drew 2.4 million visitors in its first full year of operation and is the world’s largest museum dedicated to African American history and culture.