Charles Dharapak/AP

Video: Obama speaks at African American Museum groundbreaking

'This day has been a long time coming,' president says.

President Obama and first lady Michelle Obama, along with other influential American leaders, attended the groundbreaking of the National Museum of African American History and Culture on Wednesday in Washington.

The museum's mission is to "be a place where all Americans can learn about the richness and diversity of the African-American experience, what it means to their lives, and how it helped us shape this nation. A place that transcends the boundaries of race and culture that divide us and becomes a lens into a story that unites us all."