A WALK from the history museum on the edge of St Louis’s verdant Forest Park, past grand faux-Tudor mansions on Lindell Boulevard, leads to the wealthy white neighbourhood of Central West End. Turn left on Euclid Avenue and you pass the Drunken Fish sushi restaurant, Golden Grocer Natural Foods, trendy espresso bars and Left Bank Books, displaying titles thoughtfully chosen by bibliophile shop assistants. Then these businesses suddenly stop, a block or so away from Delmar Boulevard. This is the city’s unofficial demarcation line.

The area directly to the north of Delmar Boulevard is 99% black, according to Washington University and the University of St Louis. Boarded-up and crumbling houses, dollar shops and fried-chicken outlets dominate the picture. The median home value north of Delmar is a quarter of the value of houses south of Delmar. Only 5% of residents who are 25 or older north of Delmar have a bachelor’s degree, compared with 67% south of it.

Situated on the banks of the majestic Mississippi on the boundary of Illinois and Missouri, St Louis is a border city still shaped by the racial attitudes of the old South and the property arrangements of the old north. During the decades of the great migration, when blacks from the rural South moved to cities in the north, it became one of America’s most segregated cities. St Louisians resorted to private racial covenants to prevent blacks from buying properties in white districts. “Shall St Louis be the slave master?” reads the caption of a handbill from 1916 on display at the Missouri History Museum; it shows a white man cracking a “negro-segregation” whip at a black mother and her three children to shoo them back to the slave quarters. Despite this and other efforts to persuade them, St Louisians voted overwhelmingly in favour of two ordinances that would prevent anyone buying a home in a neighbourhood with a population of more than 75% of another race. The Supreme Court struck them down in 1917, but they set the tone for race relations in the city for the following few decades.

Some say the city’s apogee was in 1904, when it hosted the World’s Fair and the summer Olympics. At the time it was America’s fourth-largest city after New York, Chicago and Philadelphia; it had the second-oldest symphony orchestra, a grand opera house, one of the world’s largest and busiest railway terminals, one of its most popular urban parks and some of the country’s best breweries, bearing Germanic names such as Griesedieck or Winkelmeyer. Others argue that the decline started in the 1950s, when the city’s population peaked at 850,000 residents. It has been downhill ever since, with a trajectory familiar to many cities in the rustbelt: deindustrialisation and depopulation, as first whites and then middle-class blacks fled to the suburbs.

Today St Louis is a shadow of its former self. With 188 murders last year, it had the highest murder rate per person in the country. Nearly all the suspects were black, as were their victims. In a city of only 315,000 residents these days, almost one-third live at or below the federal poverty level. Most of them are black. The city once renowned for its economic might and the talents of its offspring—from T.S. Eliot and Yogi Berra to Josephine Baker and Chuck Berry—is now more famous for the race riots in Ferguson, one of its suburbs.

Traces of the once-great city are everywhere. Many multinationals still call St Louis their home, from Anheuser-Busch (beer) and Ralston Purina (pet food) to McDonnell Douglas (aerospace) and Monsanto (agrochemicals). St Louis is also the biggest centre of financial-services firms outside Manhattan, with companies such as Edward Jones and Stifel Financial. Yet many of the big firms have been gobbled up: Ralston Purina has been bought by Switzerland’s Nestlé, Boeing now owns McDonnell Douglas and Monsanto is in the process of merging with Germany’s Bayer. On April 5th JAB, a German conglomerate that owns Krispy Kreme Doughnuts and other food brands, announced it was taking over another St Louis success story, with the acquisition of Panera Bread, a bakery chain, for $7.5bn.

St Louisians cringe every time one of their home-grown companies is taken over, as this tends to come with job cuts. Yet the creation of attractive takeover targets also shows the city’s knack for entrepreneurship, which endures. In 2002 Washington University, St Louis University and others teamed up to create the Cortex innovation community, built on industrial land between the two universities. Cortex is now home to about 325 companies, with names like CoFactor Genomics and Boundless, which have found a home in the Centre for Emerging Technologies, an incubator; the BioGenerator, an accelerator that works with startups for a short, intense time; TechShop, a workspace for prototyping; or another of the seven innovation centres. By next year the eighth office building will be added, along with a light-rail station connecting Cortex to the airport and a hotel. Last month Microsoft announced that it will move its regional headquarters into the new Cortex building next year.

These efforts are showing hopeful results. Nearly 15,000 new college-educated millennials moved to St Louis between 2000 and 2014, according to the Pew Charitable Trust, which makes the city millennials’ fourth-most-popular destination, eclipsing both Chicago (11th) and Seattle (19th). In a report on the rise of innovation districts, the Brookings Institution, a think-tank, cited Cortex as one of the seven best examples. On April 11th and 12th Dennis Lower, the chief executive of Cortex, played host to 12 other mayors to parade these achievements. Until recently, no forward-looking mayor would have bothered to travel to St Louis for inspiration.

Long-term success, however, requires this renaissance to include the northern part of the city. Here, too, there are some encouraging signs. Half the students at the Collegiate School of Medicine & Bioscience, a magnet high school attracting the best pupils in the area, which was developed by Cortex, are black. It is a start.