From the Rev. Martin Luther King Jr.'s birthplace to the nation's capital, Americans of all backgrounds on Monday were honoring the legacy of the slain civil rights leader.
Here's a snapshot of some of the major events commemorating MLK Day:
The King Holiday Observance in Atlanta
In King's hometown of Atlanta, historic Ebenezer Baptist Church held its annual Martin Luther King commemorative service.
King served as co-pastor of Ebenezer Baptist from 1960 until his assassination in 1968. His funeral was held at the church.
Monday's church service was intended to engage "members of various religious traditions, and state, national and international governments," according to The King Center, which was established by the civil rights icon's widow Coretta Scott King.
The keynote speaker Monday was Bryan Stevenson, founder and executive director of the Equal Justice Initiative in Montgomery, Alabama. King's youngest daughter, Dr. Bernice King, also delivered remarks.
For those outside of Atlanta, "The King Center encourages the world to engage in volunteer service in tribute to the work and life of Dr. King."
The MLK Memorial Breakfast in Washington, DC
More than 1,100 people, including members of Congress, attended the nation's longest-running event honoring King's legacy -- the Dr. Martin Luther King Jr. Memorial Breakfast in Washington.
Sheyann Webb-Christburg, who was a young girl when she joined the "Bloody Sunday" march from Selma to Montgomery, Alabama, delivered the keynote address.
President Trump visits MLK Memorial
President Donald Trump and Vice President Mike Pence left the White House just after 11 a.m. Monday and arrived at the Martin Luther King Jr. memorial on the National Mall in Washington.
Trump gave very brief remarks at the unannounced visit. He and Pence laid a wreath at the site but the President did not mention King in his extremely brief remarks to the pool.
"Good morning, everybody. It's a great day. A beautiful day. Thank you for being here. Appreciate it," Trump said.
King Day at the Dome in Columbia, South Carolina
Sens. Cory Booker and Bernie Sanders, both likely presidential candidates, were in Columbia, South Carolina, to deliver remarks at the King Day at the Dome.
The event included a morning prayer service, a march lineup at Zion Baptist Church, and then a State House rally. At the rally, Sanders attacked Trump's record on issues of race and said he was dividing Americans.
"In terms of racism, and it gives me no pleasure to say this, we today have a president who is a racist," Sanders said at the rally, citing Trump's role in the "birther movement" that falsely questioned Barack Obama's birthplace.
"And over the last two years as president, Trump has done what no other president in modern history has done. And that is, instead of bring us together as Americans, he has purposely and aggressively attempted to divide us up by the color of our skin, by our gender, by our nationality, by our religion and by our sexual orientation," Sanders said.
The National Civil Rights Museum in Memphis, Tennessee
At the site where King was assassinated, the National Civil Rights Museum at the Lorraine Motel was expecting as many as 7,000 to 8,000 visitors. Attendees celebrated the 90th anniversary of King's birth, which was last Tuesday.
"The focus of the celebration is community service and social and economic justice," the museum said.
"Activities include daylong performances, youth-centered edutainment, a healthy community pavilion and the museum experience. In the spirit of service, the Museum will hold its annual Mid-South Food Bank Drive and Lifeblood Drive, and serve as a center for community resources and engagement."
MLK Jr. March in San Antonio, Texas
The Martin Luther King Jr. March in San Antonio bills itself as the largest march in the nation, with about 300,000 participants at last year's event.
Among the participants was Julian Castro, the former secretary of Housing and Urban Development who is running for president in 2020.
"No matter what the color of your skin is, where you come from, you should count. We need to get back to that in this country. If I'm president, that's what I'm going to do," he told CNN affiliate KSAT.