Every year, World Population Day is observed on July 11th, aiming to increase people's awareness of various population issues, such as the importance of urbanization, genderequality, poverty, health, and human rights. In 2025, under the theme "Empowering Youth to Build the Families They Want," the United Nations draws attention to the largest generation of young people in history, many of whom are coming of age in rapidly urbanizing contexts. Urban centers remain key to understanding these demographic patterns, as cities continue to attract populations seeking opportunity, stability, and access to essential services. Today, more than half of the global population resides in urban areas, a share projected to increase to 66% by 2050.
More than half of the world's population resides in urban areas, with over 4 billion people depending on cities as their main environment. According to the United Nations’ latest report on populations in cities, this number is expected to continue to increase over the next 50 years, prompting cities worldwide to strive to find better ways to accommodate their growing population while transitioning to more sustainable urban practices. To highlight this responsibility, the United Nations has declared July 11th the World Population Day.
Under this year’s theme, “To Leave No One Behind, Count Everyone,” the UN aims to also draw attention to the importance of data collection for reflecting societal diversity. The growth of world cities is part of this equation as an important measure for understanding global population trends. The following list presents the top 20 cities worldwide in 2024, ranked by the population size of their metropolitan areas. Comparing the results to the previous editions, the only cities to reduce their size are the two cities from Japan, Tokyo and Osaka. The highest growth rates can be observed in African mega-cities, Kinshasa and Lagos, while China continues to be the most present country in the list, with 5 metropolises present in the top 20: Shanghai, Beijing, Chongqing, Tianjin, and Guangzhou.
According to the World Population Clock, the human population reached 8 billion on November 15th. According to the UN, this milestone represents a celebration of human longevity due to improvements in public health and medicine, but it also comes with warnings about inequality, limited access to food and resources, and environmental damage. Despite the impressive number, the annual World Population Prospect report shows that the global population is growing at the slowest rate since 1950, and it predicts a continued deceleration in the second half of this century.
As more than half of the worldpopulation lives in cities, an estimated 55.7%, according to UN-Habitat’s latest reports, the urban challenges are growing exponentially. The UN expects this number to increase to 68% by 2050, with close to 90% of this increase taking place in Asia and Africa. Accelerated urbanization can pose significant risks, such as increasing inequality, poverty, sectorized development, social exclusion, and pollution. In this context, a well-balanced urban agenda becomes crucially important in achieving inclusive, safe, and sustainable cities.
Half of the world’s population now lives in cities, according to UN-Habitat’s latest reports. While this number is set to increase to two-thirds by 2050, urban challenges are growing exponentially, making it more crucial than ever, to transform our cities. Annually, the world population review assesses the growth of cities and the number of residents living in metropolitan areas, to understand global evolution trends. In 2022, the list of the top 20 most populated countries remained similar to the 2021 edition, with a slight change in numbers and positions. Tokyo kept its status as the world’s largest city, with 37 million inhabitants, while Delhi and Shanghai, followed in second and third positions.
Comparing the results to the 2021 edition, the only decrease that can be seen in the top 20, involves both Japanese cities, Tokyo and Osaka. The rest of the list had, on average, a growth of 1.8% in the total of people residing in metropolitan areas. In fact, African cities Kinshasa in the Democratic Republic of Congo and Lagos in Nigeria gathered the highest rates, with respectively a 4.39% and a 3.54% increase in residents in 1 year. The largest city in the American continent is still Sao Paulo in Brazil, followed closely by Mexico City and Buenos Aires in Argentina, further down the table. In Europe, Istanbul is the most populous, with more than 14.5 million residents.
As cities grow in scale, dimensions, and amplitude, taking in 60% of the world population, the United Nations has designated the 31st of October as “World Cities Day”, an opportunity to talk furthermore about global urbanization, addressing challenges, encouraging opportunities across borders and highlighting responses. Focusing this edition on the theme of “Adapting Cities for Climate Resilience”, this day, part of Urban October, seeks to raise awareness about the climate crisis and its repercussions on the built environment.
Cities, at the center of the global challenges, are hubs for institutions, society, economy, commerce, and transportation. Understanding the importance of “Thinking the City”, we have compiled in this roundup, articles published by ArchDaily’s editors that offer planning tools and guidelines, tackle the different components of the urban realm and highlight worldwide as well as contextual questions and responses.
According to the United Nations’ latest report on populations in cities, by 2030, “urban areas are projected to house 60 percent of people globally and one in every three people will live in cities with at least half a million inhabitants”. Growing in both size and number, cities are hubs of government, commerce, and transportation, and in 2021, the world’s 20 largest cities are home to half a billion people. In fact, one in five people worldwide lives in a city with more than 1 million inhabitants.
Below, we have rounded up the top 20 megacities in the world of 2021, according to the number of people that live in their metropolitan area. While Tokyo is the largest city on a global level, with a total of more than 37 million residents, the majority of the most populous cities in the world are in the two most populated countries, China and India. Among these, we have 5 metropolises in China, Shanghai, Beijing, Chongqing, Tianjin, and Guangzhou, and 3 in India, Delhi, Mumbai, and Kolkata. The largest city in the American continent is Sao Paulo in Brazil with 22 million people, followed by Mexico City and Buenos Aires in Argentina. Istanbul takes the 13th position with one part of the city lying in Europe and the other part in Asia.
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AFAIR UI 2018 Design Competition: "Lost and Found"
Have you ever had the idea to occupy a space that is soulless and lacking of identity? When you are in a transitional space, for example, can your surroundings leave you any meaningful/memorable expressions or a positive impact? Residual spaces. They are spaces of nothingness, physically and psychologically. Ironically, their widespread existence tend to be abandoned/forgotten and considered useless and hopeless. "Lost and Found" challenges you to explore and address meaningful expressions of these spaces. How far can we dig in the potentials that correspond to the surroundings of these residual spaces? Either solving an issue or embracing a local phenomenon, architecture contributes to kick-start positive changes to our society. Just look around you. After all, they are just lost spaces, in need to be found.
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Zaryadye Park / Diller Scofidio + Renfro. Image Courtesy of Zaryadye Park
When it comes to urbanism these days, people’s attention is increasingly turning to Moscow. The city clearly intends to become one of the world’s leading megacities in the near future and is employing all necessary means to achieve its goal, with the city government showing itself to be very willing to invest in important urban developments (though not without some criticism).
A key player in this plan has been the Moscow Urban Forum. Although the forum’s stated goal is to find adequate designs for future megacities, a major positive side-effect is that it enables the city to organize the best competitions, select the best designers, and build the best urban spaces to promote the city of Moscow. The Forum also publishes research and academic documents to inform Moscow’s future endeavors; for example, Archaeology of the Periphery, a publication inspired by the 2013 forum and released in 2014, notably influenced the urban development on the outskirts of Moscow, but also highlighted the importance of combining urban development with the existing landscape.
Last month, the eleventh edition of the Moscow Urban Forum released the topic of the 2016 forum: "Fast-Growing Megacities: Technologies for Dynamic Development." The forum will seek to answer the following questions: Why is it so important to discuss growth and development of megacities at this time? What are the rules that determine their existence? With three days to go, organizers have announced this year’s program.
