First choose a level by typing '25', '50', '100' or '200' - then name the largest European 10K+ city in the circle/ring of that distance range (in km) as the rings expand outward from your location. You need to have your browser's location function working or the quiz will not load.
You MUST have a city within the initial distance you choose for your level - so this quiz will not work if you are not within Europe (or at least not within your level's distance of a Europe 10K+ city).
When you run out of time or end the quiz, you will see the current ring's correct answer at right (under 'Answer Stats' by your coordinates).
For example, if you choose '10' - you will be shown a circle of radius 10 km centered at your location. Naming the largest city in this circle will cause another 'ring' of radius 10 to appear outside that circle. You now need to name the largest Europe 10K+ city in that ring (but not within any previous circles/rings). If a city is not within the next ring of that distance, the ring will keep expanding by that distance until a city falls within it. So if a city doesn't fall within 20-30 km (assuming your level is 10 km), it will expand to be a 20-40 km ring, then 20-50 km and so on until a city is found within the ring.