You may have noticed we ran for a day with a photo of Big Ben of London, then a day with the Little Mermaid from Copenhagen, to see if photos have any influence on the scores. On this quiz there wasn't - London held steady on 92%, and Copenhagen crept up from 46% to 48%.
I guess "everyone" is going to guess London anyway, maybe you could try the test again with a picture of Moscow and one of Athens and see if the improve
Calling Ankara the capital of a European country is a bit of a stretch since that city is clearly in Asia, and such a small part of Turkey is in Europe. See answers above for discussion about Nicosia/Cyprus.
That would be more difficult for those who tend to type it correctly because then they'd have to waste time on deleting the extra n from the answer box.