The Big-O was a unique concept created by ECA2. The 45m tall sculpture combines expressive architecture and multimedia show design. The sculpture was the icon of the 'Big-O' Expo site during the day. At night the ECA2 multimedia presentation transformed the sculpture into a unique show that embraced the Yeosu 2012 Expo themes. The Big-O structure is formed from a circular steel truss 35m diameter supported on concrete legs. The elliptical opening was filled by a water curtain. The perimeter of the truss was lined with fire, fountain and lighting effects.