The competition to design a 6500 m² thematic pavilion and exhibition hall was announced in anticipation of the 2012 World Expo in Yeosu, South Korea. Yeosu is a peninsular city on the southern coast of Korea. With a coastline that wraps around 2/3 of the city’s perimeter, it is understandable that the theme of the expo in Yeosu is the ocean. The competition brief called for a design for a thematic pavilion that would establish Yeosu as a “blue city” and host exhibition highlighting best practices for ocean stewardship. At the time, the office was exploring a unique interest in the accident as a means of generating form. We decided to combine this interest with the ocean-themed requirements of the brief. Noting that decay of natural coastal habitats was a major problem for today’s oceans, and that artificial reefs are an effective, if expensive solution to this problem, we proposed a building that was orchestrated as a years-long, slow-motion “accident” that slowly collapsed into the sea. Once fully submerged, the pavilion would itself become an artificial reef, helping to rehabilitate Yeosu’s harbor by providing habitat for sea creatures. During the long decay, the pavilion would constantly change its shape, collapsing in an unpredictable accidental process that would produce unique and significant formal qualities. The design also called for an underwater glass bridge to be constructed after submersion that would allow visitors an intimate view of the sea life in the reef as well as a glimpse of the final accident-generated architectural form.