On the campus of Green School Bali, the Arc is a new community wellness centre designed on the existing foundations of a former temporary gymnasium. Other all-bamboo buildings on the campus feature post-and-beam construction, while the Arc employs a pioneering system of bamboo arches interconnected with anticlastic bamboo grid-shells that curve convexly along a longitudinal plane and concavely along the perpendicular section. The arches are very steep on the sides and reach a height of 14 metres; the free span of the interior area is 19 metres, allowing for the space still to be used as a gymnasium as well as for a community centre for all the campus students and teachers. The construction is 100 percent bamboo and results in a fully open-air tropical structure whose passive design, featuring high ceilings, open ends, and deep overhangs, ensures natural ventilation and year-round comfort. It is the culmination of over a decade of research into the use of bamboo as a versatile and sustainable construction material.