Thousands of people are gathering in Washington Sunday to dedicate a national memorial to slain civil rights icon Martin Luther King Jr.

President Barack Obama — the nation's first black president — is scheduled to deliver an address before a host of civil right luminaries and members of the King family, honoring the man who gave his life in the pursuit of equal rights for blacks in America.

An estimated 50,000 are expected to attend the ceremony which includes musical performances by artists including Aretha Franklin.

The dedication of the $120 million dollar statue and memorial park on the National Mall was initially set for August but was delayed because of the threat from Tropical Storm Irene.

The monument, which stands some nine-meters-tall, is the only one on the National Mall not dedicated to a president or war. The memorial is also the first on the Mall to honor an African-American.

The project took some 15 years complete. The monument features a statue of King carved out of white granite, gazing into the horizon. It is also engraved with some of the most famous quotes from the Nobel Peace Prize laureate.

Martin Luther King was assassinated on April 4, 1968 in Memphis, Tennessee .

King — a Baptist minister known for his eloquence — conducted a non-violent protest campaign in the 1950s and 1960s to end racial segregation in the southern United States.