Glass is an important architectural and construction component in twentieth century to obtain transparency. Designing a building transparent may have many reasons as political or symbolic reasons. But besides that transparency has effects as changing perception of the people, making the inside and outside ambigious, dissolving the solidity in the urban context and making the building disappear. In this paper, two monumental buildings will be analyzed in term of transparency in the urban context. First example is Fondation Cartier of Jean Nouvel, which is located on the Boulvard Raspail between buildings. Respect to the nature was one of the most important aims of the building. Second example is Louvre Pyramid of I.M.Pei which is located on the plaza between the two wings of the historical Louvre. Both buildings have a monumental effect but in terms of transparency they differ from each other. It will be analyzed if they succeeded both in the urban context and for their architects.