In interwar Zagreb, a large accumulation of newly arrived population lead to a series of new problems and urban regulation, more efficient construction and development of planned housing were in the basis of the solution. The wild settlements of the poorer stratum of the working class that sprung up along the periphery, due to non-existent infrastructure and without satisfying the subsistence minimum, became the epicenters for the spread of the tuberculosis epidemic, and the insufficient capacities of health institutions could not keep up with the needs of the patients. The state's insensitivity to proper social action has sparked a wave of noninstitutional effort aimed at creating a more humane environment for all layers of society. Also, inspired by their foreign experiences, ethically aware Zagreb architects used their craft as a tool for change and unite in groups oriented towards social engagement and the implementation of modern ideas of new construction as the only meaningful, economical and efficient solution. In addition to the formal Association of Artists Zemlja and the Zagreb Working Group, a dense network of transnational cooperation of individuals was created who focused their work on criticizing the existing situation, issuing publications, organizing exhibitions, designing and building for the needs of every person.