There is a missing ‘l’ in ‘Third Word City’ as well, but you’d have to school me on apostrophes.
I learned in grade school that to use an apostrophe to indicate possession you placed the apostrophe after the word "worlds' richest city". Placing the apostrophe between the word and the s is a contraction of the word and "is". "The world's a mean place". I rarely see what I learned in grade school used any longer. Also spell checkers do not like that use either so I think I am out of date. I attended grade school back in the 50s and many of the things I learned no longer seem accepted practice.
I will - the apostrophe is used to indicate the possessive, it is not used to make a noun plural.
Examples of the possessive are: “in England’s green and pleasant realm”, or “the cat’s meow”, or “tell who cleft the devil’s foot”. The word “of” is implied with the possessive: the realm of (belonging to) England; the meow of the cat; the foot of the devil.
The apostrophe is also used to indicate a contraction, or a dropped letter: can’t for cannot; wouldn’t for would not; it’s for it is. Many here at FR confuse the contraction for “it is” for the preposition “its”, which belongs in the same category as his, hers, ours and theirs. So you write, “it’s raining in my heart” to describe what is happening, and “when the disease reaches stage four, its prognosis is terminal.”
The apostrophe is never used to make a noun plural. If we write about the Nazis, the Clintons, the Kennedys, the Obamas - an S is added to the end of the name. In writing the plural of a common noun, like dog, boy, car, just add an S: dogs, boys, cars. If the noun ends in a Y, like gypsy, you drop the y and add IES - gypsies.