An atmosphere of "electricity and excitement" has imbued a 216-kilometre peaceful march starting in Ferguson, Mo., today and slated to end at Missouri Gov. Jay Nixon's mansion in seven days, says the president of the NAACP, which organized the protest.

"We believe a march that taps into the deep civil rights history similar to the one by Dr. [Martin] Luther King 50 years ago can bring about change," Cornell William Brooks told CBC News on Saturday.

Brooks said it will take a core group of about 100 people seven days to reach Nixon's home. 

"Fifty years ago, they had no more than 50 people that did the entire march but had 65,000  at the end," noted Brooks, who added that the aim of the march was to end racial profiling, the militarization of police and to build up trust between communities and police departments.

Brooks said the NAACP was able to end lynching when it formed 105 years ago: "You have to believe in the capacity of people to bring about justice."

'The problem with violence is that it is heard as violence.'— NAACP president Cornell William Brooks

The NAACP is calling on people to protest peacefully for 100 days.

"Dr. King said that violence is the language of the unheard. The problem with violence is that it is heard as violence."

The march started at the Canfield Green Apartments, the residential complex near where Michael Brown, 18, was shot and killed on Aug. 9 by Ferguson police Officer Darren Wilson.

Interrupting traffic, business

Monday night's announcement that Wilson, who is white, wouldn't be indicted for fatally shooting Brown, who was black, prompted violent protests that resulted in about a dozen buildings and some cars being burned. Dozens of people were arrested.

Although the demonstrations, which have also been taking place in other U.S. cities, could last for weeks in Ferguson, a sense of normalcy — or at least a new normal — has begun to settle on the city.

On Friday, numerous storefronts in the Ferguson area had their windows covered with plywood with messages painted across many of them letting neighbours know that the shops are still open.

On Saturday, police reopened several blocks of West Florissant that had been barricaded off since Tuesday, but only during daylight hours.

"There is no business," said Nick Ahmed, 41, a Palestinian immigrant who owns Elite Liquor on West Florissant. "I can't pay the rent or my electric bills."

Tracy Ballard, 44, brought her daughter, 7, to Ahmed's store to buy candy and soda, before a trip to the beautician up the street. Ballard said she wanted to show support for Ferguson businesses.

"I feel sad for the business owners," Ballard said. "It's really sad it had to come from this. We just wanted justice. If we'd have had justice, none of this would have happened."

'If we'd have had justice, none of this would have happened.' - Tracy Ballard, Ferguson resident

The protests have hurt business throughout the St. Louis area, not just in Ferguson. Protesters disrupted shopping in suburban St. Louis for the second straight day on Saturday, marching through a Trader Joe's food store in Brentwood, about 16 kilometres south of Ferguson. After leaving the store they briefly blocked a street near an interstate highway.

On Friday, three St. Louis-area malls were briefly shut down due to demonstrations. Protest organizers planned to meet later Saturday to map out their plans for the coming days.

"I served my country. I spent four years in the army, and I feel like that's not what I served my country for," said Ebonie Tyse, 26, of St. Louis as National Guard trucks and police cruisers roamed the street in front of her.

"I served my country for justice for everyone, not because of what colour, what age, what gender or anything," she said.

USA-MISSOURI/SHOOTING

A policeman and member of the National Guard detain a man demanding justice for the killing of 18-year-old Michael Brown, outside the Ferguson Police Department on Friday. (REUTERS)

Fifteen people were arrested Friday night, according to Missouri Department of Public Safety spokesman Mike O'Connell. He said charges would include peace disturbance and impeding the flow of traffic, and two people would be charged with resisting arrest and one with assault.

Nationwide protests

Elsewhere on Friday, protests in Chicago, New York, Seattle and northern California — where protesters chained themselves to trains — were among the largest in the country on Black Friday.

In Oakland, more than a dozen people were arrested after about 125 protesters wearing T-shirts that read "Black Lives Matter" interrupted train service between Oakland and San Francisco, with some chaining themselves to trains.

Later in San Francisco, a march by hundreds turned ugly as protesters smashed windows and hurled bottles and other objects at police, leaving two officers injured. Police respond by making arrests but have not said how many. Dozens of people in Seattle blocked streets, and police said some protesters also apparently chained doors shut at the nearby Pacific Place shopping centre.

APTOPIX Ferguson

Protestoes gather inside of the Westlake Center in Seattle on Friday to protest a grand jury's decision not to indict a police officer in the shooting of Michael Brown. (Joshua Trujillo/ Associated Press)

In Chicago, about 200 people gathered near the city's popular Magnificent Mile shopping district, where Kristiana Colon, 28, called Friday "a day of awareness and engagement." She's a member of the Let Us Breathe Collective, which has been taking supplies such as gas masks to protesters in Ferguson.

With files from CBC News