The document discusses different theories of urbanism through examples of cities around the world. Perspective theory is discussed through the example of Curitiba, Brazil, which transformed into an environmentally friendly city through projects like its Bus Rapid Transit system, use of green spaces to mitigate flooding, and alternative waste management. Critical theory is discussed through the example of Copenhagen, Denmark, which implemented the Five Finger Plan for transportation and development of green spaces between train lines. Normative theory is discussed through the example of the ancient city of Babylon, which was an important religious and cultural center located on the Euphrates River in Mesopotamia according to their world view.