The Congrès Internationaux d’Architecture Moderne (CIAM) was a series of international conferences held from 1928 to 1959, which played a significant role in shaping the direction of modern architecture. CIAM was founded by a group of architects, including Le Corbusier, Sigfried Giedion, and others, with the aim of addressing the challenges of urban planning and architecture in the rapidly changing world of the early 20th century.

Key aspects of CIAM include:

1. Modernist Ideals: CIAM was deeply influenced by modernist principles, advocating for functionalism, rationalism, and the use of new materials and technologies in architecture and urban planning. The members of CIAM sought to break away from the historicist and ornamental styles of the past and embrace a more streamlined, efficient, and egalitarian approach to design.
2. Functional City: One of the central concepts developed by CIAM was the idea of the “Functional City,” which proposed the rational organization of urban spaces to meet the needs of modern society. This included separating functions such as living, working, and leisure, and designing cities based on principles of efficiency, hygiene, and social well-being.
3. The Athens Charter: In 1933, CIAM produced the Athens Charter, a landmark document that outlined principles for urban planning and architecture. The charter emphasized the importance of zoning, infrastructure, and social amenities in creating healthy and functional cities. It also advocated for the preservation of historic monuments and the integration of green spaces into urban environments.
4. Regional Groups: CIAM was organized into regional groups, each focusing on specific geographical areas and urban challenges. These groups facilitated collaboration among architects and planners from different countries and helped adapt modernist principles to local contexts.
5. Legacy: Although CIAM disbanded in 1959 due to internal disagreements and shifting architectural trends, its influence on modern architecture and urban planning continues to be significant. Many of its ideas and principles, such as the Functional City and the importance of social considerations in design, remain relevant today and have shaped the development of cities around the world.

Overall, CIAM played a crucial role in promoting modernist ideals and advancing the field of architecture and urban planning in the 20th century, leaving a lasting legacy that continues to influence contemporary design practices.