The longest place name in the world belongs to Bangkok, Thailand.
Why it is true
The city's full ceremonial name is 169 letters long and translates to a long phrase describing the city's beauty and history.
Source: Geography
Would you rather be asked first?
This is the reading side of the site, so the answer is in the sentence above — that is the whole point of it. Test yourself works the other way round: the question comes on its own, and the fact and the explanation only appear once you have answered.