One of the city in Europe that I love is Paris.
What's wrong with this sentence?
It should read:
One of the cities in Europe that I love is Paris.
The rule:
The phrase "one of the," should have an object that is plural.
The structure: One of the Noun(plural)
More examples:
One of the ways to earn money online is to put Google Adsense in your site or blog.
One of the things I like about you is your thoughtfulness.
This is yet another common mistake in English essays. :)