On July 21, 1967, Minneapolis police officers passed a blazing grocery store on Plymouth Avenue on the city’s North Side as they began to clear a crowd during a second night of violence. The officers marched shoulder to-shoulder down three blocks to clear a path for firefighters and to halt looting. (The Minnesota Star Tribune)

This week is not the first time police and protesters have squared off along Plymouth Avenue in north Minneapolis. In 1967, the very same street saw some of the most destructive riots in city history. The legacy that persists from those clashes is something all sides should remember in the coming days and weeks.

That summer, 150 National Guard troops were deployed to the area. More than 30 fires blazed over three days. At least three people were wounded by gunfire, according to newspaper accounts.

While those events paled in comparison with the devastating riots that swept Detroit the same week, the Plymouth Avenue unrest had a similarly lasting impact on the community.

The most enduring effect hides in plain sight today, obvious only if you look at photos taken before the unrest. Of the dozens of storefronts that once lined the street, not one remains. Butcher shops, bakeries, a bowling alley. Koval Appliances and the Homewood Theater. All gone.

Whatever didn't burn that week would quickly fall in the name of urban renewal. By the mid-1970s, when I was growing up nearby, Plymouth was an avenue of empty lots. For a full mile between the alphabetically ordered cross-streets of Aldrich and Penn Avenues, there is exactly one pre-1967 building still standing.

Gaps have been partly filled in with cheap apartments, or with social service and government buildings, most notably the Fourth Precinct police station built in 1988. But from Aldrich to the city line at Wirth Park, there are just three commercial establishments — a liquor store, a barbershop and the Estes Funeral Chapel. From the corner where Jamar Clark was shot, it's a 20-minute walk to buy a carton of milk.

It's true that Plymouth Avenue was already declining by 1967, as many of the area's Jewish businesses followed their customers to the suburbs. But that was happening elsewhere in the city, too. What the riots destroyed forever was the original, pedestrian-friendly streetscape — the sort of community infrastructure that has helped to anchor and revive so many other Minneapolis and St. Paul neighborhoods.

There were charges of police brutality before the 1967 riots, too, and those troubles have remained. As a teenager in the 1980s, I was once stopped by a Fourth Precinct cop who didn't give me a ticket but wanted to know what a white guy like me was doing living "up here with these animals."

Activists this week warned that north Minneapolis is ready to burn, that the neighborhood is just one bullet away from Ferguson or Baltimore. History gives a loud warning of what can happen to a community once that match is struck. Scorched earth does not easily regrow.

Residents and community leaders trying to keep the pressure on for justice should do all they can to keep the protests as peaceful as they are purposeful.

And for the mayor and the police, the job should be to get to the truth of this weekend's events as quickly, honestly and transparently as possible — no matter where the trail leads.

Don't let Plymouth Avenue burn again.

Jon Coifman, of New York, was raised on the North Side and returns regularly.