The Science of Complexity has taken recent notice for its ability to explain and predict the complex phenomena in the fields leading from natural to social sciences which are unexplainable with the existing scientific theories and methodologies. Thus, applying it to architectural & urban research fields would lead to successful explanation and prediction of architectural phenomena. However, most of the existing cases concerning this issue have dealt with the conceptual or speculative appropriations of it. This study aims to investigate empirically and quantitatively complex systematic emergent behaviors revealed in architectural & urban spaces and to interpret architectural meanings of those phenomena. Power-law is utilized as a main methodology to specify the validity of emergent behaviors. The result has shown the validity of this behavior in a variety of architectural & urban phenomena and that it follows the power-law; in the distribution of human movement rate in a large multi-use shopping mall, its rental store area, room area in a building, and in the city context, traffic volume, building height, and unit/building count of apartment complexes. With this result, it could be said that architectural & urban spaces are complex adaptive systems and that uneven rules act on the formation or development of them.