Type 'easy' or 'hard' to begin the quiz. Easy is a 5-degree grid, hard is a 2.5-degree grid. Then, try to name the LARGEST European city in each grid square which fits the category label for each square. To name a city, you must first click on the grid square to make it have a GREEN border. Then, type in the city answer for that square followed by a '.' (a period). You are given a score from 0 to 100 based on your answer's population compared to the largest city accepted in that square (100 being you named the largest city).
LETTER: means the city starts with that letter.
NUMBER RANGE: (such as 2-5, 10+) means the city contains that many letters (excluding spaces and special characters).
POPULATION RANGE: (such as 50-100K) means the city has that range for its population.
2+ WORDS means the city name has 2 or more words (words denoted by a space or hyphen).
At the end of the quiz the largest population missed answer will show in each unanswered square, and for those answered the largest city will be listed if you didn't answer it.
Quiz Takers 
for some reason if you type Mora and then Quintanar it lets you have 2 cities in the same square
There are some problems in the the expert level quiz. Such as:-
All populations are from my source, citypopulation.de, and using city proper populations. I don’t know where you are getting some of these claims? Antwerp fills in a square, as does Ghent and Masstricht. The short city names are possibly part of a longer name where I accept a shortened version.
It is any city instead of biggest city. The color of the dots show that Maastricht is bigger than Stein for example. Also the towns of Son, Mol and Lent are all real. Son is one of the towns in Gemeente Son en Breugel since they are considered 2 different towns and Lent is next to Nijmegen.
Uusikapunki isn’t accepted for some reason
It’s Uusikaupunki
fun fact – kaupunki has the same origin as köping. Sweden-finland connection, both use köping for some cities.
needs more time on advanced level (and probably on expert too)
yeah tons of squares – i’ll bump those up.
Shouldn’t Ankara be accepted for one of those middle squares in Türkiye in beginner mode?
only European Turkish cities are in this quiz. Ankara considered part of Asia. It’s a Cyprus city in that square.
Ah of course, thank you
What is the city in west scotland in beginner?
Look closely, there is somewhere else in that square other than west scotland
Coleraine
At INT level I got all the squares cleared (269 of them) and the timer stopped. But the country counter still showed only 42/43 but with no countries remaining.
The same anonymous country fault appears on completion of the ADV level also: all 1118 squares completed and no countries remaining, but country counter still showing only 42/43 done. There’s something strage about Maribor also, as Slovenia showed as complete even though that sqaure was not entered.
There’s something amiss with the quiz now (at INT level). I’ts showing that there is only one country outstanding (RUS) but also showing that only 41/43 counries are complete. The city counter show 268 of 269 cities completed. There are two empty grid squares in Russia, but using the grid from the Europe City Latitude Coverage quiz for comparison (and various mapping sites), there is nothing in there above 10k to find. So how can the quiz be finished? (The empty grids are those south of Ukhta and east of Kandalaksha.)