Green building is becoming more and more popular method in modern architecture. With the rising number of world population there is greater need for progress and development of urban areas, but that unfortunately means removal of green areas for further building construction. In this final paper we will take a closer look at green building, more precisely green roofs, and will answer the most burning questions about green roofs. Some of which are: what are green roofs, when were they created, their development throughout the history, what kinds of green roofs exist, green roof layers, while the impact of green roofs on the building and the environment will be explained in more detail. Also, paper will touch upon negative impact of green roofs as well as detailed description of one selected example of green roof. The main goal of this paper is to get familiar with the concept of building green roofs, describe in which way they contribute to the environment with many of their positive effects and encourage thinking of ways we can improve nature and return nature to the top of the buildings.