silver-plated to refract light and prevent outside heat from penetrating the building; air in the inflatable components and a Brine system irrigating them cooled the interior. All of this created a temperate building, meaning that the climate control system only needed to work against body heat produced by visitors and heat given off by equipment used in the exhibition. This way the organisers could make use of a system that was much more sustainable and inexpensive than conventional air conditioning. Cities of water This square had no walls, so its contents were visible from outside. The exhibit was about water as an "urban resource" and a "natural element in the process of improving quality of life in cities". Extreme water This square symbolised the moment when a wave breaks on the beach. It was divided into two areas: the first was the sensorial area with 120 mobile seats where audiovisuals were projected; the second was the ideas area with interactive platforms, images and texts about water and its risks. Oikos, water and energy This exhibit was about getting energy from water. Shared water This thematic square showed visitors how political divisions affect the management of water. Aquatic inspirations This square hosted the show El hombre vertiente, created by the Argentine Pichón Baldinu, six times a day. Participants pavilion Country pavilions More than one hundred countries, plus dozens of companies and NGOs, participated in Expo 2008. The confirmed list had these 104 countries (arranged in alphabetical order): The 17 autonomous communities of Spain and two autonomous cities of Ceuta and Melilla also participated, as did as the United Nations and the European Union. The pavilions for official participants were divided into eight large buildings and into five differentiated eco-geographical areas within the Expo 2008 Exposition site. Those areas were: Islands and Coasts Oasis Ice and snow Temperate Forests Tropical Rainforests Mountains and High Plains Grasslands, Steppes and Savannahs Rivers and Flat plains The joint pavilions corresponding to the eco-geographic areas of Grasslands, Steppes and Savannahs, Tropical Rainforests and Islands and Coasts, were built by the organisers to house the pavilions of countries of Sub-Saharan Africa, Latin America and the Caribbean Community (CARICOM), respectively. The total surface area of the participating countries pavilions was 61,667 m2. Spain and the region of Aragon, as hosts, had their own separate pavilions. The Spain Pavilion was designed by Patxi Mangado, and the Aragon Pavilion, which