A detailed case study describing the new low energy 'Atlantic Pavilion' in Portugal, which provides a large venue for a range of cultural and sporting events. The pavilion combines a number of low energy cooling techniques including natural ventilation, thermal mass and good shading. When compared to a more convention design, without these energy saving techniques, It is calculated that, a total energy savings of 36% in winter and 63% in summer is achieved. The shape and orientation of the building plays a key role in the passive design. The orientation was chosen to take advantage of solar radiation on the southern façade. This maximises exposure from the sun during the coldest time of the year and allows direct shadowing during the summer, saving energy usage.