Ross Kemp filmed a television documentary last summer almost 15 years after a political peace settlement was signed.
He clutched a massive round chunk of masonry which broke a police officer's leg in North Belfast and sheltered behind police vehicles as petrol bombs hurled by a crowd of angry Union flag wrapped loyalists exploded inches away and sent flames into the hot night air.
"I never really grasped the intensity of it. The surreal thing is that this is a suburban street," he said.
Serious violence broke out on July 12 last year, the culmination of the Orange Order marching season.
It followed a decision to prevent Protestant marchers from walking through a street of mainly Catholic residents in North Belfast.
Lines of officers in boiler suits with large shields and batons confronted crowds of loyalists crammed into a narrow street; protesters waving flags and hurling missiles, jumping on top of police vehicles to launch ineffectual kicks.
Some were knocked over back by powerful and sudden jets of water from hulking water cannons which filled the narrow street from side to side.
Kemp said during the programme: "The money that has been spent today could be spent so much better bringing both sides of the community together rather than what this has done, which is to widen them further."
The cost of four days of rioting was part of a wider bill of £28 million picked up by the taxpayer for policing parades for eight months last year.
Kemp's programme was about Northern Ireland 15 years after the 1998 Good Friday peace agreement which largely ended armed violence.
"There is a generation of people, a lot of young people in Milton Keynes and other places who don't really understand the situation, don't really understand the Good Friday Agreement," he said.
He interviewed a member of a dissident republican supporting group in Londonderry, who opposed the peace process, examined munition pockmarks in the walls from rocket attacks on the city's police station and visited peace lines in parts of Belfast designed to keep Protestant and Catholic apart.
He interviewed loyalists who claimed their British culture had been threatened by restrictions on the flying of the Union flag of Britain and spoke to heavily tattoed loyalist band members and children guarding bonfires of wooden pallets from Catholics.
The former EastEnders star said he had never really seen that kind of tension exhibited in Northern Ireland before and expressed surprise that more peace walls exist today than before the Agreement, one 60 feet high separating communities in west Belfast.
"The size of that wall for me was a bit of a surprise. It is a suburban street. One minute Woodvale (in West Belfast) was like Ealing and the next it was not and that happened very quickly," he said.
He added: "Those walls are there at the democratic will of the people and the worst thing is when politicians use the democratic will of people for their own ends.
"It takes time and compromise, which is a hard word for most people to come out of their mouths, we cannot force compromise."
He said the level of personal threat in North Belfast did not compare to other programmes he has made, in Afghanistan or during a confrontation in a jungle when he wondered would he see his family again.
The only missile he was hit by in North Belfast was a can of beer.
"I should have caught it. I could have done with a drink," he said.
Ross Kemp: Extreme World is on Sky 1 at 9pm tonight.