Since the late nineteenth century, factors such as increasing industrialisation, urbanisation, technological advances, political events, and population growth have profoundly influenced architecture and related disciplines. This shift from traditional values became apparent in evolving living conditions, daily realities, and urban environments, making the “modern” evident across various domains ^[1][23]. Modern architecture, finding the appropriate solutions to the concerns of the Industrial Revolution, introduced new perspectives and approaches in architecture and urbanism ^[2][24]. As society modernised, advancements across various sectors laid the groundwork for architectural designs that catered to new materials and incorporated scientific and technical innovations. Modern architecture means the liberation of the future from the past, as determined by particular cultures and times and reflected in a spectrum of buildings and ideas ^[3][25].

Architects united under the Congres Internationaux d’Architecture Moderne (CIAM) to collaboratively address housing issues. Active from 1928 to 1959, CIAM was pivotal in propagating the Modern Movement worldwide. Its design tenets encompass modular construction, standardisation, varied plan solutions, and the optimisation of natural and topographical elements ^[4][5][26,27].

At CIAM 2 (Frankfurt, 1929) and CIAM 3 (Brussels, 1930), delegates addressed the “Existenzminimum” concept, which pertained to housing affordable on a minimum wage. This strategy was extensively used to tackle housing deficits, substandard living conditions, and to adjust to post-war societal shifts ^[6][7][18,28]. CIAM’s influential ideas and resolutions subsequently shaped housing projects globally ^[5][27].

Following CIAM IV (1933), which set the “functional city” principles for urban planning, the Athens Charter of 1943 further articulated the core tenets for housing estates. The charter advocated for the partitioning of urban areas into functional zones and designing residential sectors based on topography, open spaces, climate, and greenery. It underscored the importance of enhancing urban living conditions and solidified the foundational ideology for housing estates ^[8][29].

Post-World War II, there was a push for innovative approaches to comfort in design, construction, and stable living conditions ^[9][30]. The “Hansaviertel”, showcased at the 1957 Interbau (International Construction Fair) in West Berlin, was a counter-response to East Berlin’s social realism. It epitomised modern living in high-rises set within a green and orderly urban framework, echoing the Athens Charter’s principles ^[10][31].

Rapid, standardised housing construction and urban planning strategies emerged in Europe to swiftly address housing shortages, adhering to the Athens Charter principles ^[6][18]. Housing production reached its zenith in the late 1960s and early 1970s, leading to larger-scale and taller housing estates. While large European housing estates initially followed similar design principles—like expansive block layouts and separated functions—clear distinctions emerged along certain design components ^[11][2]. Notably, Eastern European housing estates were typically more expansive, uniform, and of lesser build quality due to economic constraints compared to their Western counterparts. The socialist ideas further contributed to the homogeneous urban aesthetic of Eastern European cities ^[6][18].

In Western and Eastern European cities, several modern city planning examples based on CIAM principles stand out: Bijlmermeer in Amsterdam (1966–1972), Gropiusstadt in Berlin (1962–1975), Nowa Huta in Krakow (1958–1962), and Invalidovna in Prague (1950–1965). These projects, while diverse in typology, all embody radical modern principles. Notables are their functional urban architectural design achievements and the standardisation of solutions, serving as exemplary models, despite any differences among them ^[6][18].

While modern architecture improved living standards and produced notable examples, it sometimes compromised the quality of architectural and urban designs. As the CIAM principles became increasingly radical and standardised, urban planning often lost its touch ^[6][18]. In 1972, the Pruitt Igoe residential complex in St. Louis, designed by Minoru Yamasaki in 1955, was demolished due to issues such as severe poverty, crime, racism, and social decay. This event marked both the decline of large-panel construction in Western nations and symbolised the end of the modernist era. Pruitt Igoe stands as a poignant example of the limitations and miscalculations of modernist urban ideals when contrasted with real-world conditions. Yet its demolition also heralded the emergence of new architectural thought ^[12][13][32,33]. It is crucial to note that while some modernist housing projects faced challenges, many remain as treasured architectural assets. In our era of commercialised spaces, there is a renewed appreciation for the Modern Movement and its enduring architectural legacy that merits preservation.

Being aware of the existing background enables us to understand the risks and threats and promotes the sustainable and adaptive use of architectural heritage.

In 1923, the founding of the Republic of Turkey catalysed significant urban shifts. This era, marked by foreign interventions, migrations, and economic flux, ushered in diverse societal transformations. Eager to establish an autonomous nation, Turkey embarked on holistic modernisation efforts spanning economic, social, institutional, and urban sectors ^[14][34]. As cities rebounded from wartime devastation, the 1930s saw Turkey’s embrace of modern architecture. Western-inspired mass housing projects, cooperatives, and rental homes became pillars of the state’s modernisation vision ^[15][35]. Established in 1926, Emlak & Eytam Bank bolstered construction efforts, while the 1930s heralded a surge in cooperative housing. By 1935, Bahçelievler in Ankara was initiated as the inaugural garden-city housing model, setting a precedent for subsequent cooperative developments ^[16][36].

From 1923 to 1950, Turkey embraced an architectural approach that was both modern and nationalistic. This was in line with the state-centric development model, where modernisation was pursued by mirroring Western standards yet within the framework of national identity ^[17][37].

After World War II, Turkey experienced heightened social mobility. Migration trends reshaped lifestyles, leading to a surge in the population of civil servants and workers inclined to apartment living in industrialised cities. The 1944 Civil Servants Law catalysed the creation of numerous housing estates ^[18][38]. In 1946, the foundation of Emlak Kredi Bank boosted credit accessibility and tax incentives, paving the way for the emergence of housing projects with reinforced concrete slab block construction. The 1950s marked a significant shift as Turkey began opening up, integrating liberal policies and forging international connections. Despite its insular approach during World War II, Turkey began engaging globally ^[19][20][39,40]. This era was characterised by universalism and rationalism, highlighted by Turkey’s entry into the United Nations (1945), the adoption of a multi-party system (1946), endorsement of the Marshall Plan (1947), and NATO membership (1952) ^[21][41]. From 1950 to 1980, the previous dominant state-centric policies began to transition towards liberalism, and with increased private sector involvement in industrialisation, rapid urbanisation ensued ^[17][37].

The 1965 Condominium Ownership Law marked a pivotal shift towards the proliferation of apartment buildings. With a surge in housing demand, new zoning rights were granted, leading to a rise in multi-storey apartment developments ^[19][22][39,42]. Urban density increased through the 1960s and 1970s. The 1980s ushered in innovations in construction materials and technology. Following the military intervention, comprehensive transformations occurred across socio-cultural, economic, and political spheres. Legislation in 1981 and 1984 catalysed housing estate developments, favouring mass housing production and supporting major projects. This was in response to housing shortages and expanding informal settlements. A departure from national identity resulted in overbuilt urban environments ^[17][20][23][37,40,43].