President Barack Obama will lead his nation in homage Wednesday to Martin Luther King, at the spot where the civil rights icon voiced a soaring dream of equality 50 years ago.

In a moment of high symbolism, America's first black president will reflect on King's legacy and the long march, which still beckons to fulfill the hopes of the "I have a dream" speech, delivered from the steps of the Lincoln Memorial in Washington.

The United States reflects on one of the turning points of its recent history starting this weekend when it marks the 50th anniversary of Martin Luther King's March on Washington.

Some 150,000 are expected Saturday on the National Mall to re-enact the moving civil rights rally where King delivered his iconic "I Have a Dream" speech from the Lincoln Memorial.

Civil rights icon Martin Luther King Jr is being remembered in a Washington, D.C. exhibition held to tie-in with the 50th anniversary of his famous march on the U.S. capital.

"One Life: Martin Luther King, Jr", takes a look back at the epic sweep of the slain Nobel laureate's life and times.

In the more than four decades since the Rev. Martin Luther King was assassinated on the balcony of Memphis' Lorraine Motel, about 900 U.S. cities have named local streets for him. Memphis is not one of them, though there is a stretch of expressway bearing his name.

Now Memphis officials will consider a naming a key downtown street for the civil rights icon after years of inaction that some say reflects a sense of shame and denial in the city where he was cut down.

U.S. President Barack Obama drew inspiration Sunday from the civil rights struggles of Martin Luther King in facing down today's political gridlock in Washington.

"When met with hardship, when confronting disappointment, Dr. King refused to accept what he called the 'is-ness' of today. He kept pushing towards the ought-ness of tomorrow,'" Obama told a crowd of thousands.