This is a journey in the world of art history with the purpose of showing and stressing the real role of architecture in famous paintings.  Usually considered just a support and background to the scene represented, architecture is instead a subject itself, and a fundamental one, of the painting. By confronting, for example,  several paintings of a religious character, it can easily be seen how the authors represent the evolution of the real or ideal world of architecture and of the context, devoting more attention to this than to the biblical or evangelical scene which was generally chosen by the client.  When architecture and nature play their role without anybody or anything interfering, they establish a dialogue with each other with great freedom, in different historical ages, and maybe even in contemporary ones.