The world's most populated places are, in rough order, Mumbai in India (13.6 million people), Karachi in Pakistan (13 million), Delhi in India (11.3 million), Istanbul in Turkey (11.3 million), Sao Paulo in Brazil (11 million), Moscow in Russia (10.5 million), Seoul in South Korea (10.4 million), Shanghai in China (10 million), Beijing in China (9.5 million), Mexico City in Mexico (8.8 million), Tokyo in Japan (8.7 million), Jakarta in Indonesia (8.5 million), and New York City in the United States (8.3 million).

The most populated places at the country level are Monaco, a nation-state in Europe that is the most densely populated sovereign nation, with 32,000 people in just two square kilometers, and Singapore, with 4.6 million in 707 square kilometers. Macau and Hong Kong, mostly autonomous special administrative regions in China, are also extremely populous, with 520,400 and 7 million in 28.6 and 1,099 square kilometers respectively. If Macau were an independent nation, it would have the highest population density in the world.

Altogether, there are eight cities with populations over 10 million, at least eight cities with population densities over 20,000 people per square kilometer (seven in India and one in Bangladesh), and at least several additional cities with population densities between 10,000 and 20,000 people per square kilometer. For reference, a typical town or village has a population density of about 100-1,000 people per square kilometer, while the average world population density, if only the land is counted, is approximately 43 people per square kilometer. in general, the world's most populated places are found in south and east Asia.

The city with the highest population density in the world, and by extension one of the most populated places, by a factor of almost 100%, is Dhaka, the capital of Bangladesh. With 6.7 million residents living in an area of about 154 square kilometers (59.4 square miles), Dhaka is often known as the rickshaw capital of the world, with 400,000 rickshaws running daily. Like the rest of Bangladesh, Dhaka is culturally related to India, its neighbor to the east.

Despite fears over overpopulation, some of the most populated places in the world are some of the most interesting places to live. Though most of the most populated cities except Tokyo, Beijing, and New York City have huge slum areas, there are also large, well-developed portions of the city which are culturally, economically, and intellectually vibrant. With the global human population increasing by about 60 million people per year, and more than half of humanity living in cities, learning to hope with highly populated areas is the wave of the future. With careful planning, highly populated cities can be pleasant, with large parks and open space, as well as highly productive economically.