U.S. President Barack Obama helped dedicate a national memorial Sunday to slain civil rights icon Martin Luther King Jr, declaring that the nation must follow King's example by continuing to strive and struggle for a better country..

In his address, President Obama — the nation's first black president — said King “stirred our conscience” and helped make the Union “more perfect” through his campaign for racial equality.

He said said the monument was to the collective achievements of the luminaries of the civil rights movement, adding that it attest to the strength and courage of all those who helped bring about change.

An estimated 50,000 people attended the ceremony which included musical performances and speeches by a host of civil rights leaders, politicians, and several others.

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 $120 million dollar project took some 15 years complete and 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.