Doors and windows are most common things which we encounter in everyday life. Our life is characterized by these architectural structures. We enter into and exit from buildings through doors. We go to work through the entrance door into our offices. We come back home through the doors and we feel safety and security inside. Though we are kept inside we see the outside through windows. As modern people, we live in cities. And this means that our lives are determined by urban buildings. We move in and out of houses. Indeed the "in and out" of all buildings is possible only because there are openings on the walls. Doors and windows therefore define the inside and the outside of our existential spatiality. They separate and at the same time connect our spatial lifeworld.