Crowds grew silent Wednesday as bells rang out 39 times in Atlanta and Memphis for the age the Rev. Martin Luther King Jr. was at the time of his assassination.
Cities across the United States honored King with ceremonies and performances, as well as reflections on what today's civil rights advocates can do to carry forward his legacy 50 years after his death.
Speakers challenged listeners to push for justice and equality, as they expect King would have today. And King's son, Martin III, said that movements, including Black Lives Matter and the movement against gun violence led by students who survived a school shooting in Parkland, Florida, give him hope.
"If even then, the future -- not the past -- was what made us a movement, I believe we carry on the King tradition best by focusing on the here and now as King did as he led the civil rights movement," Eleanor Holmes Norton, Washington's nonvoting delegate to Congress, said just after noon at a wreath-laying ceremony at his memorial near the National Mall.
King's youngest child, Bernice, said he would be excited about some of today's movements, including Black Lives Matter, efforts to quell gun violence and #MeToo campaigns against abuse of women, she told CNN.
"I'm sure that he would be making connections with these movements to make sure that they had what they needed in terms of understanding organizational strategy and planning so that they could bring about effective change," Bernice King, now 55, told Wolf Blitzer.
Perhaps the grandest, most sweeping memorial was in Memphis, where King was slain while standing on the balcony of the Lorraine Motel.
The daylong tribute there -- which featured speeches, videos, and singing and spoken-word performances -- was largely held in the courtyard of the motel, now home to the National Civil Rights Museum.
Some people at the event held signs reading, "I am a man." They were reminiscent of the signs carried in 1968 in that city by sanitation workers whose strike King had come to support.
Rev. Jesse Jackson -- one of only two surviving members of King's entourage on the day he was shot -- was among the speakers at the Memphis tribute.
Here's a look at some of the events that took place to honor King's legacy:
A commemorative ceremony on the balcony of the Lorraine Motel included an interfaith liturgy, musical tributes, and a ceremonial changing of the wreath outside Room 306.
The Rev. Michael Pfleger, a Catholic priest and activist against street violence on Chicago's South Side, told the crowd that King's "loyalty was to God, and his faith is what summoned him to his activism."
"Dr. King was uncompromising in his commitment to eradicate war and racism and poverty, Pfleger said.
"Martin Luther King Jr. was uncompromising in his charge to subpoena the conscience of America, and demand that America stand before the seat of morality and face her hypocrisy and make good on the promises that she put down on paper," he added.
He said King believed the church ought to be "dangerous, dangerous to evil, dangerous to injustice."
So, as King stood on a motel balcony, "evil and the forces of hate sought to stop him and shut him up only to find out that a bullet could silence his voice but not his message, nor the truth that lived in him," Pfleger said.
Pfleger challenged the crowd to not just simply remember King and "relegate his life to some nostalgic or historic event, and then continue on with business as usual."
"Because if we do, then we become the present day co- conspirators of his assassination, Pfleger said.
As he wrapped up his speech, the bell from the historic Clayborn Temple rang 39 times as part of the International Moment of Reflection. Then, a person in the crowd yelled "let freedom ring."
When the bell stopped ringing, Pfleger and Jackson helped place a red and yellow wreath on the balcony, where King was shot.
Later on Wednesday, an "evening of storytelling" was held at the nearby Crosstown Concourse. Featuring civil rights leaders such as Jackson, it explored how past activism has fed into current movements.
In the city of his birth, the Martin Luther King Jr. Nonviolent Peace Prize was awarded to lawyers Benjamin Ferencz, for his work prosecuting German Nazi leaders at Nuremberg, and Bryan Stevenson, for his work to make mandatory life-without-parole sentences for all children 17 or younger unconstitutional.
Civil rights attorney Benjamin Crump introduced Stevenson as someone who "shines like a beacon in the dark."
The Ebenezer Baptist Church choir sang the National Anthem and "Lift Every Voice and Sing" early Wednesday afternoon before a game between the Washington Nationals and the host Atlanta Braves.
Members of King's fraternity, Alpha Phi Alpha, attended a service at the historic Ebenezer and carried a wreath into the sanctuary.
King joined the black fraternity in 1952 as a Boston University student.
"He took everything we are and wrapped a cloak of courage around it," Greg Gray, a fraternity leader in the Atlanta area, said during the service.
Bernice King addressed the church from the pulpit, quoting her father.
"My father fought his entire life to ensure the inclusion of all," she said.
She added: "He fought for justice and equity and peace."
She said her late mother, "helped to shape and define that legacy so that the world would remember his teachings."
"Mine eyes have seen the glory of the coming of the Lord," she said, repeating the last line of the speech her father gave the night before he died.
At the King Center, Elvera Louise Winston and her daughter, Susan Michelle Winston, both of Lithonia, also praised King's widow, Coretta Scott King.
"Coretta kept the legacy going," said Elvera, 71.
Elvera, who lived most of her life in the Chicago and Indiana area, said her parents raised her to know about King.
"He has been with me all my life," she said.
Her mother is from Alabama, where blacks could not use water fountains during the Jim Crow era, Elvera said.
"All the rules changed mostly because of Martin Luther King," she said.
At the King Center, members of his family placed a wreath at the crypts of King and his widow, Coretta Scott King.
Events in the nation's capital started at 7 a.m. ET with a morning prayer vigil at the Martin Luther King Jr. Memorial.
A silent march then took place from the King memorial to the National Mall, site of the hours-long ACT to End Racism Rally, which featured speakers, including religious leaders, artists, and activists.