First choose any World 50K+ pop city by entering it and choosing it in the drop-down box. Then, name any World 50K+ city in each 500 km circle/ring as the rings expand outward from your city of choice, trying to name SECOND LARGEST city in each circle. The first circle will include your city of choice as a possible answer.
PLEASE NOTE - You must type a '.' (period) after each city to submit it to prevent answering another city with a name you would be have to type to get your answer. If multiple cities have the name you submitted, only the largest one will be counted.
You accumulate points based on the population of the city you named in relation to the second largest city in the circle. A smaller city’s point total will be the ratio of its population to the largest, so if you name a city of 75K people and the largest city has 100K, you get 75 points. Naming the largest city will get you points based on the ratio of the 2nd largest city's population to the largest city's.
When you run out of time or end the quiz, you will see the current ring’s 2nd largest city at right (under ‘Answer Stats’ by your coordinates).
For example, if you choose ‘Paris’ – you will be shown a circle of radius 500 km centered at Paris. Naming any city in this circle (including Paris) will cause another ‘ring’ of radius 500 km to appear outside that circle, however - you will want to try naming the SECOND LARGEST city you can to get more points. After completing that circle, you now need to name any 50K+ World city in the new ring (but not within any previous circles/rings), again trying to name the 2nd largest city. If there are not two cities within the next ring of that distance, the ring will keep expanding by that distance until two cities fall within it.
Quiz Takers 
Finland-Estonia is missing (31 km at closest)
also “trinidadtobagovenezuela” doesn’t work
added Fin/Est – you need the ‘and’ for trinidadandtobago
I thought you used the same naming practices as sporcle (you can omit “and” and “or”)
no, but you can just do ‘trinidad’ or ‘bosnia’ for example for a good number of quizzes to replace the full country name.
But there is a bridge between Sweden and Denmark (sorry for swearing)
I don’t believe it’s built on land embankments like Bahrain Saudi and Malaysia Singapore. most quiz sites do not include Sweden Denmark among bordering countries
I don’t know about that land embankment stuff, but Malaysia Singapore are absolutely not bordering countries just like Sweden and Denmark. Though the opposite is mostly considered with Bahrain and RSA, even though Google Maps say otherwise.
Malaysia and Singapore are often considered bordering by other quiz sites and resources. Just depends on your definition.
OK but what about DRC and Tanzania? Technically they actually don’t share any land border and they are less than 47.6km apart.
a lake is considered a land border I don’t think a single site would say otherwise.
There’s some asymmetries such as “UK Antigua” working but “Antigua UK” not working. Similarly “St Kitts Antigua” doesn’t work while the reverse does. There’s probably more
Also agreed, if bridges don’t count then Denmark/Sweden shouldn’t be here, the Oresund bridge is quite similar to the King Fahd Causeway (which disqualifies Saudi Arabia/Bahrain), it has an artificial island in the middle and all.
yeah will try to get a few more of those added. My site and other quiz sites generally count Singapore-Malaysia and Bahrain-Saudi (and don’t count Sweden-Denmark) as land borders as they are built on land embankments. So I will leave as-is for those.
“USA-Russia” doesn’t register. Also, if bridges disqualify, then Sweden-Denmark should not be included.
also, Philippines-Malaysia should be included as there are Philippine islands very close to northeast Borneo.
it’s “US-Russia” that will take. will add Philippines-Malaysia.
What US and UK territory is counted for their entry?
Virgin Islands. Both sets.