All Bus Stops on London Bus Route N137

Based on the clues, can you guess these European cities which start with each letter of the alphabet?

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

Click on every square of the world map which contains an urban agglomeration with a population of at least 10 million.

Drag the flag onto the correct country. Careful, though! One wrong move and the game ends.