The National Mall in Washington is getting a new, long-awaited museum dedicated to the experience of African Americans.

U.S. President Barack Obama and other dignitaries – including former first lady Laura Bush – helped break ground Wednesday on the National Museum of African American History and Culture.

Mr. Obama called on the museum to serve as an inspiration to future generations of Americans. He said the new museum is “not just a record of tragedy, but a celebration of life.''

He also said it “should stand as proof that the most important things in life rarely come quickly or easily. It should remind us that though we have yet to reach the mountaintop, we cannot stop climbing.”

Congressman and former civil rights leader John Lewis spent years trying to get lawmakers to approve the museum project. He said the museum is essential.

Lewis said, “we must tell the story, the whole story, the 400-year story of African American contributions to this nation's history from slavery to the present.”

The museum will be the 19th to open on the mall and is being built within view of the Washington Monument, on the same ground where African slaves wher once traded.

Organizers said the design is inspired by African-American metalwork and also evokes African roots.

Officials have collected 20-thousand historical items from around the country. Some of the collection is already being shown at a special gallery at the Smithsonian's American History museum.

The $500 million museum is expected to attract more than 3 million visitors each year when it opens in 2015.