MEMPHIS, Tenn. — With thoughts on the past and eyes to the future, thousands marched and sang civil rights songs Wednesday to honor the Rev. Martin Luther King Jr., the “apostle of nonviolence” silenced by an assassin 50 years ago.

At events ranging from a jubilant concert to a solemn wreath-laying, admirers around the country took time to both reflect on King’s legacy and discuss how his example can apply to racial and economic divides still plaguing society.

Among the largest gatherings was a march through the Mississippi River city where the civil rights leader was shot dead on a motel balcony in 1968. Memphis Police estimated a crowd of as many as 10,000 people.

The Rev. James Lawson, who invited King to Memphis 50 years ago to assist with a strike by underpaid sanitation workers, helped lead the march and said more progress is needed toward King’s goal of equality for all.

“I’m still anxious and frustrated,” said Lawson, his black hair turned gray. “The task is unfinished.”

Speaking in King’s hometown of Atlanta, the Rev. Bernice King recalled her father as a great orator whose message of peaceful protest was still vital decades later.

“We decided to start this day remembering the apostle of nonviolence,” she said during a ceremony to award a prize named for her father.

As painful as losing her father was, she said she wouldn’t change history.

“Actually, I’m glad that everything happened the way that it happened because I can’t imagine the world that we live in without the contributions of Martin Luther King Jr. and Coretta Scott King and the sacrifice that they made,” she said.

Before the Memphis march, the rapper Common and pop singer Sheila E had the crowd dancing and bobbing their heads. Then, as the march began, people locked arms or held signs as they chanted and sang songs such as “We Shall Overcome.”

“We know what he worked hard for, we know what he died for, so we just want to keep the dream going,” said Dixie Spencer, who came to the march from nearby Hardeman County, where she’s an NAACP leader. “We just want to make sure that we don’t lose the gains that we have made.”

Martin Luther King III addressed marchers at the end of their route, focusing on the triple evils of poverty, racism and war. “There’s something wrong in our nation where a minimum of 48 million people are living in poverty. That’s unacceptable. We must do better. America should be embarrassed about having people living in poverty.”

In the evening, the Atlanta events were set to end with a bell-ringing and wreath-laying at King’s crypt to mark the moment when he was gunned down on the balcony of the old Lorraine Motel on April 4, 1968. He was 39.