What is it about cities that make people vote Democrat?

[HansOslo]

Are cities overseas (Western Europe/Canada) as liberal as the ones in the United States?

It seems to me that the European centre-right parties have had much more success in appealing to an urban electorate; why is that? 

The center-right definitely does better in the large cities in Scandinavia. Most of the larger cities here in Norway are ruled by some sort of bourgeois-coalition.  There are a lot of state and municipal employees in the city, as well as minorities and poor people. But there are also a lot of doctors, lawyers and other professionals, and they skew heavily to the center-right, and they are more likely to vote than the base voters of the socialist parties.

These voters might be “liberal” on issues like abortion and homosexuality, but so are the mainstream parties of the right. But they also want lower taxes, the freedom to choose which schools they send their children to and generally more personal freedom. That is why they vote for the center-right.

[HansOslo]

While Sweden/Norway/Finland is often cited most often when it comes to centre-right cities and centre-left country side there are other examples as well.

In Spain Madrid is centre-right while the rural Andalucia is left-wing.

Oh and as far Sweden goes, it's also worth noting that it's only Stockholm that's solid right of the big three cities. Gothenburg is won by the side that wins the election, and Malmö leans left and only go for the right when they win big.

I have always wondered why that is. I can see why Göteborg is solid for Socialdemokratarna, since there used to be a lot of industry in and around Göteborg. And with the industry come blue collar workers and trade unions, who vote for the parties of the left.
But why doesn’t this apply to Stockholm as well? Were there less of an industrial presence in Stockholm?