The third book of the 20th Century Tunja´s collection describes the national policy of building model popular neighborhoods as key in the development of the periphery of the city and the multiple urbanizations still recognized today. The chapters deal with: the first, the transformation in the period; the second, forms of urban growth; the third, the first planning experiences in Tunja: the plan of the future city; the fourth, the infrastructures and their impact on Tunja's morphology such as roads and railway lines; the fifth, the provision of public household services; the sixth, public spaces: streets, parks, and squares; the seventh, industrial facilities and facilities and the eighth, public housing and informal urbanization.