Top 5 cities of the world

- Top 5 cities of the world with cleanest air
- Top 5 cities of the world with most polluted air
- Top 5 most beautiful cities of the world
- Top 5 most expensive cities of the world
- Top 5 cities in the world to live
- Top 5 cities world most populated
- Top 5 biggest cities in the world
- Top 5 oldest cities in the world
- Top 5 safest cities in the world
- Top 5 expensive cities in the world
- Top 5 beautiful cities in the world
- Top 5 populated cities in the world
- Top 5 coldest cities in the world
- Top 5 nightlife cities in the world
- Top 5 smart cities in the world