Ambiguous city names
The question is: what countries in the world — other than in the US — allow more than one city to have the same name? In the US, city names are only required to be unique to the state, so there are quite a few cities that have the same name (Kansas City, MO & Kansas City, KS; Portland, OR & Portland ME; etc.)
England is a special case (as usual). First of all, there is the whole problem of whether the “country” is the UK, or if you should treat England, Scotland, Wales, etc. as separate countries. I opt for the latter. But even considering only England, there are many cities with similar names. Wikipedia lists four cities named “Newcastle” but they usually disambiguate by specifying a location, like “Newcastle upon Tyne”. Unfortunately, that still leaves Newcastles in Herefordshire, Shropshire (sometimes called Newcastle on Clun), and Staffordshire (Newcastle-under-Lyme). But forcing people to specify a shire name to disambiguate a city name in England seems a bit harsh.
Are city names required to be unique in Canada? I can’t think of any non-unique examples, but that doesn’t mean there aren’t any. [when researching "Newcastle", I discovered that there used to be two places in Canada called Newcastle, one in New Brunswick that has since merged with the city of Chatham, and one in Ontario that still exists. But I still don't know the answer to the question of whether there are now any ambiguous city names in Canada.]
There are no less than 15 cities called Newcastle in the US, but luckily they are all in separate states.
Why is this important to ZAT? Well, to make a city in the US unique, you have to say what state it is in. In most other countries, just saying the city name and the country name make it unique.