Today, approximately 56 percent of the global population or 4.4 billion people reside in urban areas. This trend is expected to continue, with the urban population projected to more than double by 2050. At that time, nearly 70 percent of humanity, or an additional 2.3 billion people, will live in cities. The scale and speed of urbanization present both opportunities and challenges. Cities are economic powerhouses, generating over 80 percent of the global Gross Domestic Product (GDP). When effectively managed, cities can harness the potential to drive sustainable growth through increased productivity and innovation. However, the benefits of urbanization are contingent upon addressing the growing need for affordable housing, robust infrastructure, basic services, employment opportunities, and much more. The concentration of people often leads to strained infrastructure and increased resource demand in urban areas. Rapid urbanization often outstrips infrastructure development, resulting in inadequate housing, transportation, water, sanitation, and energy. Notably, nearly 1 billion urban poor live in informal settlements, often near economic opportunities but lacking basic infrastructure and services. Further, 1.6 billion urban dwellers are estimated to face housing inadequacies by 2025. In this context, proactive urban planning and management are crucial, especially in developing countries where most of the global urban expansion is expected to occur. Building cities that are smarter, greener, and more inclusive has never been more self-evident. Having gone through the full urbanization process, the Republic of Korea can offer insights on how to tackle key urban challenges of overcrowding and inadequate infrastructure and service delivery, while achieving economic, social, and environmental goals.