REEF CYCLE is a startling and iconic pavilion for the Yeosu World Expo, a dynamic structure that dramatically alters its form over the life of the expo and beyond, eventually becoming a beneficent contribution to the world’s marine life. REEF CYCLE does more than symbolize the life and future of the ocean - it actually participates in the ocean’s processes, transforming into a living part of the ocean’s ecology. Architecture exists as events. This is true although we typically conceive it as a singular act of permanence. Whether we choose to recognize it or not, the built environment necessarily changes with time and transforms according to ecological processes. Classically, architects build permanent structures. Architectural form refers to a work of perfection that stands in contrast to function, the messy, changing processes of life that occur through and around it. But buildings are not still frames of perfection. The potential for change and decay is necessarily constructed into the DNA of every building at the outset. If we adopt the long view (i.e. look past the day the ribbon is cut), ideal form is not corrupted by decay, but exists in dynamic relationship with it. As architects, we can orchestrate the outcome of this relationship, direct the ecological processes of change throughout the life of the building. Taking this position allows architecture to transcend mere formalism and come to terms with the exigencies of material life. It also provides new opportunities for strategically designing mutability, for architecture to develop a new kinesthetic sense.This is why we are not simply proposing a building; we are proposing a process that includes a building. The process we propose will provide Yeosu with a compellingly beautiful pavilion that embraces the 2012 World’s Expo theme of “the ocean” not through representation, but by evolving into part of the ocean life itself and participating in the sea rehabilitation effort.