World Map 30 X 32 Puzzle by Cities With at least 1 Million People
Type a city whose urban agglomeration holds at least 1 million people: its piece and the ones around it (within a 'radius' of 2) appear. Pieces that aren't reached by any city are shown at the start. Pieces that are only reached by cities that aren't in the Top 250 and that are 2 pieces away are shown at the start, too.
List of cities taken from citypopulation.de - to learn the 250 largest ones try this quiz