From June to September, over 5.5 million people visited the Expo 2008 in Zaragoza. More than 100 countries and international organisations presented in 140 pavilions the world exhibition’s topic “Water and sustainable development”. The exhibition’s most emblematic buildings were the 76-metre-high Water Tower “Torre del Aqua” containing the sculpture Splash, and the Bridge Pavilion built across the river Elbro. High value was not only put on the architectural design of the pavilions, but also on the pavilions’ air-conditioning and ventilation systems which had to provide a maximum level of thermal comfort.