This paper examines evolutionary patterns in tourism from an economic geography perspective. It proposes a new theoretical model where endogenous changes to the tourism circuit lead to a dualism in market and spatial structures: powerful conglomerates share the markets with a competitive fringe and core resorts share tourism spaces with peripheral destinations. The model illustrates graphically the interaction of market and spatial forces and studies implications for resort development. The short run analysis examines the relationship among origin regions, core and peripheral resorts; smooth and abrupt long term patterns are subsequently explored. The paper also gives directions to operationalize the model and suggests themes for future research.