Putting them together as one urban area doesn't make sense. It's like saying Manchester and Liverpool are the same city; or New York and Philadelphia.
Massa is the largest city in an urban area stretching from Viareggio to Sarzana, which is why it's here
I think most quizes consider they are.
That aside, great quiz! I had just over half this time, would love to do better so I'll revisit for sure. :D
Bournemouth is 465k max, not 553k.
Northampton is 212k max, not 359k.
Brighton is 475k, that's if you include Hove, not 596k.
Kingston upon Hull is 260k, not 403k.
And they were just the smaller UK towns that didn't seem to ring true.
The above numbers are all from Wiki.
Blue - National Capital
Black - Everything else
Heilbronn: City Prop=127k; UArea=180k; UAgglo=333k
Würzburg: City Prop=124k; UArea=164k; UAgglo=196k
Turns out, I was wrong.