Type 'easy' or 'hard' to begin the quiz. Easy is a 15-degree grid, hard is a 10-degree grid. Then, try to name the SECOND LARGEST city in each grid 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 2nd largest city accepted in that square (100 being you named the 2nd largest city). If you guess the largest city it will be based on the ratio of the 2nd largest city's population to the largest.
At the end of the quiz the 2nd largest city will show in each unanswered square, and for those answered the 2nd largest city will be listed next to your score if you didn't answer it.
Quiz Takers 
Added a few more to make it 75 total cities.
I see only 70. I would suggest Vyborg, Helsinki, and any of the larger Ukrainian cities that have de-Sovietized their names recently, like Kropyvnytskyi, Kamianske, or even Kyiv.
I’d forgotten Dnipro’s old name but I wiped it from my memory since it was so much easier to remember the new short one. 😀
Try refreshing – you should see 75 now.
fugging
Considered a ‘locality’ not a city by the census.
No Bratislava?
Great quiz concept although I personally would enjoy it more if all entries were cities with completely different names (ex. Mexico City), rather than just different romanization (ex. Beijing).
For additional cities to add, two very notable ones in Japan are Tokyo (formerly Edo) and Osaka (formerly Naniwa).
Doh, never mind re Tokyo – did not see the second page of the quiz
“Beiping” isn’t just a different Romanization. It’s bei + ping, meaning “northern peace”, as opposed to bei + jing, meaning “northern capital”.
If you’re considering adding to the list (I’m just going to list the current names so this post doesn’t become a spoiler in the event you add them):
Rodriguez, Philippines (1982, but in the process of reverting to its original name)
Mandaluyong, Philippines (1931)
Sasmuan, Philippines (1991) (for the same reason Fugging changed theirs)
Thiruvananthapuram, India (1991)
Gurugram, India (2016)
Adama, Ethiopia (2000)
Why did Constantinople get the works?
That’s nobody’s business but the Turks.