Thousands of Americans gathered on the National Mall in Washington, D.C., on Sunday to dedicate a memorial to the nation's foremost civil rights leader, Dr. Martin Luther King Jr.

Martin Luther King is not only a hero of Americans, he also is a hero of the world, and he pursued the universal dream of the people of the world, Sculptor Lei Yixin said through a translator in August, before Hurricane/Tropical Storm Irene pushed back the dedication of the memorial to Oct. 16, The Christian Science Monitor reported Sunday.

Aretha Franklin, poet Nikki Giovanni, and President Barack Obama were among those present at the ceremonies.

The sculpture of King with his arms crossed appears to emerge from a stone extracted from a mountain, The Atlanta Journal Constitution reported Sunday. The design was inspired by a line from the famous I Have a Dream speech in 1963: Out of the mountain of despair, a stone of hope.

King's 1963 March on Washington Speech Galvanized U.S. Civil Rights Movement

King's Dream speech during the 1963 March on Washington for Jobs and Freedom galvanized the civil rights movement -- and was pivotal in helping to change the political culture and build a national consensus to pass the U.S. Civil Rights Act of 1964 -- a landmark legislative achievement in the United States that outlawed all forms of discrimination against black men and women, including racial segregation. The legislation was signed into law by President Lyndon B. Johnson, who would also later sign the U.S. Voting Rights Act of 1965 -- another landmark piece of of legislation that outlawed discrimination in voting practices.

The sculpture is the centerpiece of the $120 million memorial, which also includes a 450-foot-long granite wall inscribed with 14 quotations from King's speeches and writings. King is the first person who was not a U.S. president to be memorialized on the National Mall, The Associated Press reported.

King's older sister, Christine King Farris, said she witnessed a baby become a great hero to humanity. She said the memorial will ensure that her brother's legacy will provide a source of inspiration worldwide for generations to come.

He was my little brother, and I watched him grow and develop into a man who was destined for a special kind of greatness, King Farris said. To the young people in the crowd, she said that King's message is that Great dreams can come true and America is the place where you can make it happen.

King's willingness to sacrifice himself for our country, to fight for a dream he believed in, like justice and equality, really gave a foundation for President Obama becoming the president, the White House said, The Associated Press reported.

President Obama, First Lady Michelle Obama, and daughters Malia and Sasha paid an advance visit to the memorial Friday evening as journalists were kept back in vans on a service road leading to the site, situated near the Tidal Basin between the Lincoln Memorial and the Jefferson Memorial.