The document lists the three largest urban areas by population in each continent. In Europe, the largest urban areas are Moscow, the Ruhr Area in Germany, and Sao Paulo in Brazil. The largest urban areas in North America are New York City, Mexico City, and Los Angeles. In Australia, the largest urban areas are Sydney, Melbourne, and Brisbane. In Asia, the largest urban areas are Tokyo, Seoul, and Osaka. In Africa, the largest urban areas are Cairo, Lagos, and Johannesburg.