First choose any Europe 10K+ city by entering it and choosing it in the drop-down box. Then, name the 3 largest 10K+ Europe cities in each 100km circle/ring as the rings expand outward from your city of choice. The first circle will include your city of choice as a possible answer if it is in the 3 largest 10K+ cities in that area. As you enter cities you will see their rank within the current ring (1st, 2nd or 3rd largest) above their marker.

When you run out of time or end the quiz, you will see the current ring’s largest population correct answer at right (under ‘Answer Stats’ by your coordinates).

For example, if you choose ‘Paris, France’ – you will be shown a circle of radius 100km centered at Paris. Naming the 3 largest cities in this circle (Paris among them in this case) will cause another ‘ring’ of radius 100km to appear outside that circle. You now need to name the 3 largest 10K+ European cities 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 100-200km, it will expand to be a 100-200km ring, then 100-300km and so on until a qualifying city is found within the ring.

Want only one city per ring?
Europe 100 Km Expanding Circles Challenge – Choose City