Country by letter #15: All countries starting with the letter O.

Can you name the cities that are served by the world's 50 busiest airports?

Fill in the map by guessing languages. When you guess a language, all the countries that use it as an official language will be filled in.

20 random countries have been removed from the map of the world! Can you identify them in 3 minutes?

You will be shown 10 random numbers between 1 and 100 without knowing what's next. Your task is to put them in order! But beware, if a number cannot be placed, the quiz ends...