Oh no, the world map has been covered up with circles! To clear a circle you have to type a city inside it that is either: A)One of the largest B)One of the furthest from a larger city
Colour hints: Big circles: - red indicates lack of cities
City circles: - red means it's not one of the largest - green means it's not one of the furthest from a larger city
Dot size depends on number of circles cleared by that city
Data for 1M cities from citypopulation.de, data for smaller cities from geonames.org
Cities with no more than 10,000 inhabitants are only considered if they have no larger city within 100 km
When stuck you can try moving the mouse over cleared circles to read the corresponding cities: one of them might work for a nearby circle!
Each city dot is associated to the big circle closest to it (when measuring distance between centres): when you guess that big circle, the city will turn brighe green. It could be the case that the city isn't an answer for that cirlce!