How Much Diversity Does a Modern City Need?

As a general rule, being inaccessible or remote is not good economically for a city, but it can make a place more interesting. That`s what drew me to spend a few days in Duluth, Minn., a city hardly touched by the demographic changes that have swept through so much of the country in recent decades.

Duluth sits up high in the northeast quadrant of Minnesota, touching Wisconsin. Few go through the city to get to somewhere else, unless they are on board a long ship loaded with iron pellets: The city is a major port on Lake Superior at the terminus of the Saint Lawrence Seaway. There is an interstate highway, I-35, but it dead-ends in Duluth. The airport is small. Amtrak trains from Minneapolis stopped running in 1985....