Western European Cities in the Top 20: World vs. Europe

The presence of Western European cities in "top 20 largest" lists depends entirely on the geographic scope:

World's 20 Largest Urban Agglomerations (UN World Urbanization Prospects)

Zero. The world's largest cities are overwhelmingly in Asia (Tokyo, Delhi, Shanghai, Dhaka, Beijing, Mumbai, Osaka, etc.), Africa (Cairo, Lagos, Kinshasa), and the Americas (São Paulo, Mexico City, NYC, Buenos Aires). No Western European metro cracks the global top 20.

Europe's 20 Largest Urban Agglomerations

Seven are in Western Europe:

1. London (UK) – ~14.3M
2. Paris (France) – ~13.1M
3. Madrid (Spain) – ~6.8M
4. Barcelona (Spain) – ~5.6M (often ranked higher than Berlin/Rome depending on definition)
5. Berlin (Germany) – ~4.5M (city proper 3.8M; metro larger)
6. Rome (Italy) – ~4.3M
7. Milan (Italy) – ~4.3M (metro ~8.2M)

Also notable: Amsterdam (Netherlands) ~2.5M metro, Brussels (Belgium) ~2.1M metro—often in Europe's top 20 depending on city-proper vs. metro definitions.

Key Distinction: "City proper" vs. "Metropolitan area" vs. "Urban agglomeration" rankings yield different orders. The list above uses urban agglomeration (continuously built-up area), the standard for international comparison.